Inclisiran: A Novel Agent for Lowering Apolipoprotein B-Containing Lipoproteins

A promising therapy for fatty liver disease: PCSK9 inhibitors

BACKGROUND

Fatty liver disease (FLD) poses a significant global health concern worldwide, with its classification into nonalcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD) contingent upon the presence or absence of chronic and excessive alcohol consumption. The absence of specific therapeutic interventions tailored to FLD at various stages of the disease renders its treatment exceptionally arduous. Despite the fact that FLD and hyperlipidemia are intimately associated, there is still debate over how lipid-lowering medications affect FLD. Proprotein Convertase Subtilisin/ Kexin type 9 (PCSK9) is a serine protease predominantly synthesized in the liver, which has a crucial impact on cholesterol homeostasis. Research has confirmed that PCSK9 inhibitors have prominent lipid-lowering properties and substantial clinical effectiveness, thereby justifying the need for additional exploration of their potential role in FLD.

PURPOSE

Through a comprehensive literature search, this review is to identify the relationship and related mechanisms between PCSK9, lipid metabolism and FLD. Additionally, it will assess the pharmacological mechanism and applicability of PCSK9 inhibitors (including naturally occurring PCSK9 inhibitors, such as conventional herbal medicines) for the treatment of FLD and serve as a guide for updating the treatment protocol for such conditions.

METHODS

A comprehensive literature search was conducted using several electronic databases, including Pubmed, Medline, Embase, CNKI, Wanfang database and ClinicalTrials.gov, from the inception of the database to 30 Jan 2024. Key words used in the literature search were "fatty liver", "hepatic steatosis", "PCSK9", "traditional Chinese medicine", "herb medicine", "botanical medicine", "clinical trial", "vivo", "vitro", linked with AND/OR. Most of the included studies were within five years.

RESULTS

PCSK9 participates in the regulation of circulating lipids via both LDLR dependent and independent pathways, and there is a potential association with de novo lipogenesis. Major clinical studies have demonstrated a positive correlation between circulating PCSK9 levels and the severity of NAFLD, with elevated levels of circulating PCSK9 observed in individuals exposed to chronic alcohol. Numerous studies have demonstrated the potential of PCSK9 inhibitors to ameliorate non-alcoholic steatohepatitis (NASH), potentially completely alleviate liver steatosis, and diminish liver impairment. In animal experiments, PCSK9 inhibitors have exhibited efficacy in alleviating alcoholic induced liver lipid accumulation and hepatitis. Traditional Chinese medicine such as berberine, curcumin, resveratrol, piceatannol, sauchinone, lupin, quercetin, salidroside, ginkgolide, tanshinone, lunasin, Capsella bursa-pastoris, gypenosides, and Morus alba leaves are the main natural PCS9 inhibitors. Excitingly, by inhibiting transcription, reducing secretion, direct targeting and other pathways, traditional Chinese medicine exert inhibitory effects on PCSK9, thereby exerting potential FLD therapeutic effects.

CONCLUSION

PCSK9 plays an important role in the development of FLD, and PCSK9 inhibitors have demonstrated beneficial effects on lipid regulation and FLD in both preclinical and clinical studies. In addition, some traditional Chinese medicines have improved the disease progression of FLD by inhibiting PCSK9 and anti-inflammatory and antioxidant effects. Consequently, the inhibition of PCSK9 appears to be a promising therapeutic strategy for FLD.

Nanoparticles and siRNA: A new era in therapeutics?

Since its discovery in 1998, the use of small interfering RNA (siRNA) has been increasing in biomedical studies because of its ability to very selectively inhibit the expression of any target gene. Thus, siRNAs can be used to generate therapeutic compounds for different diseases, including those that are currently 'undruggable'. This has led siRNA-based therapeutic compounds to break into clinical settings, with them holding the promise to potentially revolutionise therapeutic approaches. To date, the United States Food and Drug Administration (FDA) have approved 5 compounds for treating different diseases including hypercholesterolemia, transthyretin-mediated amyloidosis (which leads to polyneuropathy), hepatic porphyria, and hyperoxaluria. This current article presents an overview of the molecular mechanisms involved in the selective pharmacological actions of siRNA-based compounds. It also describes the ongoing clinical trials of siRNA-based therapeutic compounds for hepatic diseases, pulmonary diseases, atherosclerosis, hypertriglyceridemia, transthyretin-mediated amyloidosis, and hyperoxaluria, kidney diseases, and haemophilia, as well as providing a description of FDA-approved siRNA therapies. Because of space constraints and to provide an otherwise comprehensive review, siRNA-based compounds applied to cancer therapies have been excluded. Finally, we discuss how the use of lipid-based nanoparticles to deliver siRNAs holds promise for selectively targeting mRNA-encoding proteins associated with the genesis of different diseases. Thus, siRNAs can help reduce the cellular levels of these proteins, thereby contributing to disease treatment. As consequence, a marked increase in the number of marketed siRNA-based medicines is expected in the next two decades, which will likely open up a new era of therapeutics.

Serious Adverse Events of Inclisiran in Patients With Hypercholesterolemia, a Meta-Analysis of ORION Trials

BACKGROUND

Several studies have been conducted over the years to find an effective and safe therapeutic agent to treat hypercholesterolemia. Inclisiran is a novel drug being studied for its efficacy and safety in reducing low-density lipoprotein cholesterol levels in patients to reduce the risk of cardiovascular diseases. No previous study was done to review the trials for the serious adverse events of this drug. The primary objective of this research is to investigate the incidence of serious adverse events of this drug.

DESIGN

A systematic review and meta-analysis of clinical trials is performed.

METHODS

A systematic search of PubMed, Embase, and ClinicalTrials.gov, from their inception till July 3, 2023, was performed for ORION trials, studying the efficacy and safety of inclisiran. The random-effects model was used in the meta-analysis to provide a pooled proportion of serious adverse events. The risk of bias in each study was assessed by the Cochrane Risk of Bias Tool.

RESULTS

From 319 studies searched from the databases, only 8 relevant articles remained after a detailed evaluation. These studies, having a total of 4981 patients, were involved in the analysis, with a pooled estimate showing a nonsignificant incidence of serious adverse events. Each adverse event was studied individually, and product issues and endocrine disorders had the highest odds ratio among them. All included studies were classified as moderate quality.

CONCLUSION

Following systematic review and meta-analysis, we found no significant differences in any serious adverse events following the administration of inclisiran. However, larger ongoing trials will provide additional data to evaluate the safety profile of this agent.

Antihyperlipidemic Treatment Options in Statin Resistance and Intolerance

Cardiovascular disease is the global leading cause of death and hypercholesterolemia is implicated as one of its top contributors. Moreover, there is growing recognition that lower low-density lipoprotein cholesterol levels offer greater protection against cardiovascular disease. Statins are the first-line lipid-lowering agents for both primary and secondary prevention of cardiovascular disease in patients with hypercholesterolemia. However, statin resistance and intolerance lead to undertreatment in patients who would likely derive the most benefit from antihyperlipidemic drugs. Several non-statin therapies are increasingly prescribed to such patients, most commonly ezetimibe and the PCSK9 monoclonal antibodies, but numerous other options have been developed in recent years and investigations into new therapies are ongoing. The use of these non-statin therapies requires the clinician to take a highly personalized approach to cholesterol reduction in complex patients. In this review, we describe current non-statin options for statin-resistant and statin-intolerant patients in addition to areas of active research.

Targeting the Liver with Nucleic Acid Therapeutics for the Treatment of Systemic Diseases of Liver Origin

Systemic diseases of liver origin (SDLO) are complex diseases in multiple organ systems, such as cardiovascular, musculoskeletal, endocrine, renal, respiratory, and sensory organ systems, caused by irregular liver metabolism and production of functional factors. Examples of such diseases discussed in this article include primary hyperoxaluria, familial hypercholesterolemia, acute hepatic porphyria, hereditary transthyretin amyloidosis, hemophilia, atherosclerotic cardiovascular diseases, α-1 antitrypsin deficiency-associated liver disease, and complement-mediated diseases. Nucleic acid therapeutics use nucleic acids and related compounds as therapeutic agents to alter gene expression for therapeutic purposes. The two most promising, fastest-growing classes of nucleic acid therapeutics are antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs). For each listed SDLO disease, this article discusses epidemiology, symptoms, genetic causes, current treatment options, and advantages and disadvantages of nucleic acid therapeutics by either ASO or siRNA drugs approved or under development. Furthermore, challenges and future perspectives on adverse drug reactions and toxicity of ASO and siRNA drugs for the treatment of SDLO diseases are also discussed. In summary, this review article will highlight the clinical advantages of nucleic acid therapeutics in targeting the liver for the treatment of SDLO diseases. SIGNIFICANCE STATEMENT: Systemic diseases of liver origin (SDLO) contain rare and common complex diseases caused by irregular functions of the liver. Nucleic acid therapeutics have shown promising clinical advantages to treat SDLO. This article aims to provide the most updated information on targeting the liver with antisense oligonucleotides and small interfering RNA drugs. The generated knowledge may stimulate further investigations in this growing field of new therapeutic entities for the treatment of SDLO, which currently have no or limited options for treatment.

Genetic insights into the association of statin and newer nonstatin drug target genes with human longevity: a Mendelian randomization analysis

BACKGROUND

It remains controversial whether the long-term use of statins or newer nonstatin drugs has a positive effect on human longevity. Therefore, this study aimed to investigate the genetic associations between different lipid-lowering therapeutic gene targets and human longevity.

METHODS

Two-sample Mendelian randomization analyses were conducted. The exposures comprised genetic variants that proxy nine drug target genes mimicking lipid-lowering effects (LDLR, HMGCR, PCKS9, NPC1L1, APOB, CETP, LPL, APOC3, and ANGPTL3). Two large-scale genome-wide association study (GWAS) summary datasets of human lifespan, including up to 500,193 European individuals, were used as outcomes. The inverse-variance weighting method was applied as the main approach. Sensitivity tests were conducted to evaluate the robustness, heterogeneity, and pleiotropy of the results. Causal effects were further validated using expression quantitative trait locus (eQTL) data.

RESULTS

Genetically proxied LDLR variants, which mimic the effects of lowering low-density lipoprotein cholesterol (LDL-C), were associated with extended lifespan. This association was replicated in the validation set and was further confirmed in the eQTL summary data of blood and liver tissues. Mediation analysis revealed that the genetic mimicry of LDLR enhancement extended lifespan by reducing the risk of major coronary heart disease, accounting for 22.8% of the mediation effect. The genetically proxied CETP and APOC3 inhibitions also showed causal effects on increased life expectancy in both outcome datasets. The lipid-lowering variants of HMGCR, PCKS9, LPL, and APOB were associated with longer lifespans but did not causally increase extreme longevity. No statistical evidence was detected to support an association between NPC1L1 and lifespan.

CONCLUSION

This study suggests that LDLR is a promising genetic target for human longevity. Lipid-related gene targets, such as PCSK9, CETP, and APOC3, might potentially regulate human lifespan, thus offering promising prospects for developing newer nonstatin therapies.

Inclisiran for the Treatment of Hyperlipidemia and for Atherosclerotic Cardiovascular Disease Risk Reduction: A Narrative Review

PURPOSE

Inclisiran is a novel nonstatin therapy providing significant reduction in low-density lipoprotein cholesterol (LDL-C) as well as improvements in other lipid biomarkers. This review summarizes data from postapproval publications regarding the impact of inclisiran on lipids and cardiovascular risk reduction, as well as its tolerability and cost-effectiveness.

METHODS

A search of PubMed for inclisiran was used to identify articles published since its approval by the US Food and Drug Administration (FDA). Clinical research studies reporting meta-analysis; pooled patient-level trial analyses; cost-effectiveness analyses; new human data; prespecified, post-hoc, or subgroup trial analyses; and clinical trial extensions were included.

FINDINGS

The search identified 153 citations; 16 studies were included. FDA-approval trials, subsequent pooled patient-level trial analyses, and extension studies found that inclisiran, administered with and without maximally tolerated statin therapy, reduced LDL-C by ≈50%, with the reduction sustained for 4 years. Inclisiran appeared to be well tolerated, even long-term, with injection-site reactions being the most common adverse effect. A patient-level pooled analysis of data from Phase III trials suggested that cardiovascular events were reduced with inclisiran versus placebo (7.1% vs 9.4%; odds ratio = 0.74 [95% CI, 0.58-0.94]). Inclisiran is suggested to be cost-effective based the presumed cardiovascular benefit commensurate with LDL-C reduction.

IMPLICATIONS

The cardiovascular benefit and cost-effectiveness of inclisiran are promising, though not definitive. The results of a large-scale study of the effects of inclisiran on cardiovascular outcomes are expected in 2026; until then, the nonstatin therapies primarily prescribed for LDL-C reduction remain proprotein convertase subtilisin/kexin (PCSK)-9 inhibitors and ezetimibe. However, inclisiran is a reasonable alternative to, PCSK-9 inhibitors, in patients who struggle with the self-injection of or adherence to PCSK-9 inhibitors as inclisiran maintenance therapy is administered twice yearly by a health care professional.

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.

The Promise of PCSK9 and Lipoprotein(a) as Targets for Gene Silencing Therapies

PURPOSE

High plasma concentrations of LDL and lipoprotein(a) (Lp[a]) are independent and causal risk factors for atherosclerotic cardiovascular disease (ASCVD). There is an unmet therapeutic need for high-risk patients with elevated levels of LDL-C and/or Lp(a). Recent advances in the development of nucleic acids for gene silencing (ie, triantennary N-acetylgalactosamine conjugated antisense-oligonucleotides [ASOs] and small interfering RNA [siRNA]) targeting proprotein convertase subtilisin/kexin type 9 (PCSK9) and Lp(a) offer effective and sustainable therapies.

METHODS

Related articles in the English language were identified through a search for original and review articles in the PubMed database using the following key terms: cardiovascular disease, dyslipidemia, PCSK9 inhibitors, Lp(a), LDL-cholesterol, familial hypercholesterolemia, siRNA, and antisense oligonucleotide and clinical trials (either alone or in combination).

FINDINGS

Inclisiran, the most advanced siRNA-treatment targeting hepatic PCSK9, is well tolerated, producing a >30% reduction on LDL-C levels in randomized controlled trials. Pelacarsen is the most clinical advanced ASO, whereas olpasiran and SLN360 are the 2 siRNAs directed against the mRNA of the LPA gene. Evidence suggests that all Lp(a)-targeting agents are safe and well tolerated, with robust and sustained reduction in plasma Lp(a) concentration up to 70% to 90% in individuals with elevated Lp(a) levels.

IMPLICATIONS

Cumulative evidence from clinical trials supports the value of ASO and siRNA therapies targeting the synthesis of PCSK9 and Lp(a) for lowering LDL-C and Lp(a) in patients with established ASCVD or high risk of ASCVD. Further research is needed to examine whether gene silencing therapy could improve clinical outcomes in patients with elevated LDL and/or Lp(a) levels. Confirmation of the tolerability and cost-effectiveness of long-term inhibition of PCSK9 and Lp(a) with this approach is essential.

Kidney lipid dysmetabolism and lipid droplet accumulation in chronic kidney disease

Chronic kidney disease (CKD) is a global health problem with rising incidence and prevalence. Among several pathogenetic mechanisms responsible for disease progression, lipid accumulation in the kidney parenchyma might drive inflammation and fibrosis, as has been described in fatty liver diseases. Lipids and their metabolites have several important structural and functional roles, as they are constituents of cell and organelle membranes, serve as signalling molecules and are used for energy production. However, although lipids can be stored in lipid droplets to maintain lipid homeostasis, lipid accumulation can become pathogenic. Understanding the mechanisms linking kidney parenchymal lipid accumulation to CKD of metabolic or non-metabolic origin is challenging, owing to the tremendous variety of lipid species and their functional diversity across different parenchymal cells. Nonetheless, multiple research reports have begun to emphasize the effect of dysregulated kidney lipid metabolism in CKD progression. For example, altered cholesterol and fatty acid metabolism contribute to glomerular and tubular cell injury. Newly developed lipid-targeting agents are being tested in clinical trials in CKD, raising expectations for further therapeutic development in this field.

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

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

Does Genotype Affect the Efficacy of PCSK9 Inhibitors in the Treatment of Familial Hypercholesterolemia?

PURPOSE OF REVIEW

This review discusses whether patients' genotype affects the efficacy of PCSK9 inhibitors in treating familial hypercholesterolemia and how this might influence clinical management.

RECENT FINDINGS

Currently, available evidence consistently demonstrates and is in good agreement that, in general, the LDL-C-lowering effect of PCSK9 inhibitors is similar across genotypes, except for compound heterozygous and homozygous familial hypercholesterolemia (FH). However, it remains to be seen whether the comparable therapeutic effect in lowering LDL-C level also leads to a comparable degree of cardiovascular risk reduction with different genotypes. Generally, the level of LDL-C reduction following PCSK9 inhibitor treatment is similar within different genotypes. Hence, genotype is a less reliable predictor for further LDL-C level reduction on PCSK9 inhibitor therapy, and attention should be given to other external influences, especially for heterozygous FH.

Inclisiran: A New Strategy for LDL-C Lowering and Prevention of Atherosclerotic Cardiovascular Disease

Multiple lines of evidence confirm that the cumulative burden of low-density lipoprotein cholesterol (LDL-C) is causally related to the development of atherosclerotic cardiovascular disease (ASCVD). As such, lowering LDL-C is a central tenet in all ASCVD prevention guidelines, which recommend matching the intensity of LDL-C lowering with the absolute risk of the patient. Unfortunately, issues such as difficulty with long-term adherence to statin therapy and inability to achieve desired LDL-C thresholds with statins alone results in residual elevated ASCVD risk. Non-statin therapies generally provide similar risk reduction per mmol/L of LDL-C reduction and are included by major society guidelines as part of the treatment algorithm for managing LDL-C. Per the 2022 American College of Cardiology Expert Consensus Decision Pathway, patients with ASCVD are recommended to achieve both an LDL-C reduction ≥50% and an LDL-C threshold of <55 mg/dL in patients at very high-risk and <70 mg/dL in those not at very high risk. Patients with familial hypercholesterolemia (FH) but without ASCVD should lower LDL-C to <100 mg/dL. For patients who remain above LDL-C thresholds with maximally tolerated statin therapy plus lifestyle changes, non-statin therapy warrants strong consideration. While several non-statin therapies have been granted FDA approval for managing hypercholesterolemia (eg, ezetimibe, Proprotein Convertase Subtilisin/Kexin 9 [PCSK9] monoclonal antibodies, and bempedoic acid), the focus of the current review is on inclisiran, a novel small interfering RNA therapy that inhibits the production of the PCSK9 protein. Inclisiran is currently FDA approved as an adjunct to statin therapy in patients with clinical ASCVD or heterozygous FH who require additional LDL-lowering. The drug is administered by subcutaneous injection twice a year, after an initial baseline and 3 month dose. In this review, we sought to provide an overview of the use of inclisiran, review current trial data, and outline an approach to potential patient selection.

MiR-126-Loaded Immunoliposomes against Vascular Endothelial Inflammation In Vitro and Vivo Evaluation

Due to the accompaniment of vascular endothelial inflammation during the occurrence and development of cardiovascular diseases (CVD), treatment modalities against vascular endothelial inflammation have been intensively investigated for CVD prevention and/or treatment. Vascular cell adhesion molecule-1 (VCAM-1) is a typical transmembrane inflammatory protein specifically expressed by inflammatory vascular endothelial. By inhibiting VCAM-1 expression through the miR-126 mediated pathway, vascular endothelial inflammation can be efficiently relieved. Inspired by this, we developed a miR-126-loaded immunoliposome with VCAM-1 monoclonal antibody (VCAM_ab) decorated at its surface. This immunoliposome can be directly targeted to VCAM-1 at the inflammatory vascular endothelial membrane surface and achieve highly efficient treatment against inflammation response. The cellular experiment results showed the immunoliposome had a higher uptake rate towards inflammatory human vein endothelial cells (HUVECs) and can significantly downregulate the VCAM-1 expression level of inflammatory HUVECs. In vivo investigation further demonstrated that this immunoliposome displayed a higher accumulation rate at vascular inflammatory dysfunction sites than its non-VCAM_ab-modified counterpart. These results suggest that this novel nanoplatform can effectively deliver miR-126 to vascular inflammatory endothelium, opening a new avenue for the safe and effective delivery of miRNA for potential clinical application.

PCSK9 Inhibitors in Cancer Patients Treated with Immune-Checkpoint Inhibitors to Reduce Cardiovascular Events: New Frontiers in Cardioncology

Cancer patients treated with immune checkpoint inhibitors (ICIs) are exposed to a high risk of atherosclerosis and cardiometabolic diseases due to systemic inflammatory conditions and immune-related atheroma destabilization. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key protein involved in metabolism of low-density lipoprotein (LDL) cholesterol. PCSK9 blocking agents are clinically available and involve monoclonal antibodies, and SiRNA reduces LDL levels in high-risk patients and atherosclerotic cardiovascular disease events in multiple patient cohorts. Moreover, PCSK9 induces peripheral immune tolerance (inhibition of cancer cell- immune recognition), reduces cardiac mitochondrial metabolism, and enhances cancer cell survival. The present review summarizes the potential benefits of PCSK9 inhibition through selective blocking antibodies and siRNA in patients with cancer, especially in those treated with ICIs therapies, in order to reduce atherosclerotic cardiovascular events and potentially improve ICIs-related anticancer functions.

Effectiveness and safety of Inclisiran in hyperlipidemia treatment: An overview of systematic reviews

BACKGROUND

This paper aimed to comprehensively evaluate the effectiveness and safety of Inclisiran in treating hyperlipidemia through an overview of systematic reviews (SRs).

METHODS

The Cochrane Library, EMBASE, PubMed, CNKI, WANGFANG database, VIP database, ClinicalTrials.gov, and ICRT were searched electronically to collect SRs and meta-analysis of Inclisiran in hyperlipidemia treatment from the establishment of the database till May 2022. Two researchers independently screened the relevant literature, then the assessment of multiple systematic reviews tool was made into assess the methodological quality of the included studies. Data extracted were used to perform the study through RevMan5.3 software. The grading of recommendations assessment, development, and evaluation tool was used to grade the quality of the evidence of the outcomes included in the SRs. Prospero ID: CRD 42022326845.

RESULTS

A total of 10 relevant SRs were included, involving 7 randomized controlled trials. The assessment results of the assessment of multiple systematic reviews tool suggested that the quality of the SRs included needed to be improved. The reduced level of low-density lipoprotein cholesterol of the experimental group was lower than the control group, and the difference in the amount of effectiveness was statistically significant (MD = -50.13, 95%CI: -56.2 to -44.06, P < .00001). The grading of recommendations assessment, development, and evaluation results showed that out of 27 outcomes, 8 were high-quality, 3 were of medium quality, 6 were of low quality, and 10 were of the most inferior quality.

CONCLUSION

300mg Inclisiran with 2 injections a year has the best therapeutic effect, which can significantly reduce low-density lipoprotein cholesterol and total cholesterol, and increase high-density lipoprotein cholesterol levels in patients with hyperlipidemia. Inclisiran has a favorable safety profile, with no significant difference in the incidence of adverse reactions compared to a placebo. Most of the adverse effects were associated with the reaction on the injection site.

Interactions between PCSK9 and NLRP3 inflammasome signaling in atherosclerosis

Atherosclerosis is an early pathological basis of numerous cardiovascular events that result in death or disability. Recent studies have described PCSK9 as a novel target for the treatment of atherosclerosis; PCSK9 is capable of degrading LDLR on the surface of hepatocytes through the regulation of lipid metabolism, and it can function as a novel inflammatory modulator in atherosclerosis. Inflammasomes are important intracellular multiprotein complexes that promote the inflammatory response in atherosclerosis. Among inflammasomes, the NLRP3 inflammasome is particularly notable because of its important role in the development of atherosclerotic disease. After activation, NLRP3 forms a complex with ASC and pro-caspase-1, converting pro-caspase-1 into activated caspase-1, which may trigger the release of IL-1β and IL-18 and contribute to the inflammatory response. Several recent studies have indicated that there may be interactions between PCSK9 and the NLRP3 inflammasome, which may contribute to the inflammatory response that drives atherosclerosis development and progression. On the one hand, the NLRP3 inflammasome plays an important role via IL-1β in regulating PCSK9 secretion. On the other hand, PCSK9 regulates caspase-1-dependent pyroptosis by initiating mtDNA damage and activating NLRP3 inflammasome signaling. This paper reviews the mechanisms underlying PCSK9 and NLRP3 inflammasome activation in the context of atherosclerosis. Furthermore, we describe the current understanding of the specific molecular mechanism underlying the interactions between PCSK9 and NLRP3 inflammasome signaling as well as the drug repositioning events that influence vascular cells and exert beneficial antiatherosclerotic effects. This review may provide a new therapeutic direction for the effective prevention and treatment of atherosclerosis in the clinic.

Pharmacotherapy for children with elevated levels of lipoprotein(a): future directions

INTRODUCTION

Elevated lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerotic cardiovascular disease (ASCVD). With the advent of the antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs) targeted at LPA, the gene encoding apolipoprotein(a), that are highly effective for lowering Lp(a) levels, this risk factor might be managed in the near future. Given that Lp(a) levels are mostly genetically determined and once elevated, present from early age, we have evaluated future directions for the treatment of children with high Lp(a) levels.

AREAS COVERED

In the current review, we discuss different pharmacological treatments in clinical development and provide an in-depth overview of the effects of ASOs and siRNAs targeted at LPA.

EXPERT OPINION

Since high Lp(a) is an important risk factor for ASCVD and given the promising effects of both ASOs and siRNAs targeted at apo(a), there is an urgent need for well-designed prospective studies to assess the impact of elevated Lp(a) in childhood. If the Lp(a)-hypothesis is confirmed in adults, and also in children, the rationale might arise for treating children with high Lp(a) levels. However, we feel that this should be limited to children with the highest cardiovascular risk including familial hypercholesterolemia and potentially pediatric stroke.

Newer and Emerging LDL-C Lowering Agents and Implications for ASCVD Residual Risk

Multiple lines of evidence demonstrate that low-density lipoprotein-cholesterol causes atherosclerotic cardiovascular disease. Thus, targeting and lowering low-density lipoprotein-cholesterol is the principal strategy to reduce cardiovascular disease risk in primary and secondary prevention. Statin therapy is the foundation of lipid-lowering treatment, but adherence rates are low, and many individuals do not attain target low-density lipoprotein-cholesterol values. Additionally, most statin-treated patients are still at considerable atherosclerotic cardiovascular disease risk, emphasizing the need for more aggressive low-density lipoprotein-cholesterol-lowering therapies. The purpose of this review is to discuss new and emerging approaches to further lower low-density lipoprotein-cholesterol, including inhibition of ATP-citrate lyase, proprotein convertase subtilisin-kexin type 9, angiopoietin-related protein 3, and cholesteryl ester transfer protein.

PCSK9 Monoclonal Antibodies: New Developments and Their Relevance in a Nucleic Acid-Based Therapy Era

Purpose of Review

To report on recent data about PCSK9 monoclonal antibodies and to evaluate their relevance in a nucleic acid–based therapy era for lipid lowering and prevention of cardiovascular disease.

Recent Findings

New methods of PCSK9 inhibition based on nucleic acid therapeutics such as antisense oligonucleotides, small interfering RNAs, and CRISPR tools for therapeutic gene editing are reported, and interesting new data regarding the clinical relevance of PCSK9 antibodies are discussed.

Summary

Promising methods of PCSK9 inhibition are in development, and one of them, the siRNA inclisiran targeting PCSK9, has already been approved for clinical use. However, PCSK9-mAb remains the PCSK9-inhibiting tool with the longest safety data and the only one having positive cardiovascular outcome trials. An ongoing cardiovascular outcome trial with inclisiran is planned to be completed in 2026. Other forms of PCSK9 inhibition, such as antisense oligonucleotides targeting PCSK9 and CRISPR base editing of PCSK9, are still in early phases of development, and their potential clinical relevance remains to be established.

Molecular and cellular biology of PCSK9: impact on glucose homeostasis

Proprotein convertase substilisin/kexin 9 (PCSK9) inhibitors (PCSK9i) revolutionised the lipid-lowering therapy. However, a risk of type 2 diabetes mellitus (T2DM) is evoked under PCSK9i therapy. In this review, we summarise the current knowledge on the link of PCSK9 with T2DM. A significant correlation was found between PCSK9 and insulin, homeostasis model assessment (HOMA) of insulin resistance and glycated haemoglobin. PCSK9 is also involved in inflammation. PCSK9 loss-of-function variants increased T2DM risk by altering insulin secretion. Local pancreatic low PCSK9 regulates β-cell LDLR expression which in turn promotes intracellular cholesterol accumulation and hampers insulin secretion. Nevertheless, the association of PCSK9 loss-of-function variants and T2DM is inconsistent. InsLeu and R46L polymorphisms were associated with T2DM, low HOMA for β-cell function and impaired fasting glucose, while the C679X polymorphism was associated with low fasting glucose in Black South African people. Hence, we assume that the impact of these variants on glucose homeostasis may vary depending on the genetic background of the studied populations and the type of effect caused by those genetic variants on the PCSK9 protein. Accordingly, these factors should be considered when choosing a genetic variant of PCSK9 to assess the impact of long-term use of PCSK9i on glucose homeostasis.

PCSK9 inhibitors for secondary prevention in patients with cardiovascular diseases: a bayesian network meta-analysis

Background

The Food and Drug Administration has approved Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) inhibitors for the treatment of dyslipidemia. However, evidence of the optimal PCSK9 agents targeting PCSK9 for secondary prevention in patients with high-risk of cardiovascular events is lacking. Therefore, this study was conducted to evaluate the benefit and safety of different types of PCSK9 inhibitors.

Methods

Several databases including Cochrane Central, Ovid Medline, and Ovid Embase were searched from inception until March 30, 2022 without language restriction. Randomized controlled trials (RCTs) comparing administration of PCSK9 inhibitors with placebo or ezetimibe for secondary prevention of cardiovascular events in patients with statin-background therapy were identified. The primary efficacy outcome was all-cause mortality. The primary safety outcome was serious adverse events.

Results

Overall, nine trials totaling 54,311 patients were identified. Three types of PCSK9 inhibitors were evaluated. The use of alirocumab was associated with reductions in all-cause mortality compared with control (RR 0.83, 95% CrI 0.72–0.95). Moreover, evolocumab was associated with increased all-cause mortality compared with alirocumab (RR 1.26, 95% CrI 1.04–1.52). We also found alirocumab was associated with decreased risk of serious adverse events (RR 0.94, 95% CrI 0.90–0.99).

Conclusions

In consideration of the fact that both PCSK9 monoclonal antibody and inclisiran enable patients to achieve recommended LDL-C target, the findings in this meta-analysis suggest that alirocumab might provide the optimal benefits regarding all-cause mortality with relatively lower SAE risks, and evolocumab might provide the optimal benefits regarding myocardial infarction for secondary prevention in patients with high-risk of cardiovascular events. Further head-to-head trials with longer follow-up and high methodologic quality are warranted to help inform subsequent guidelines for the management of these patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01542-4.

Inhaled siRNA Formulations for Respiratory Diseases: From Basic Research to Clinical Application

The development of siRNA technology has provided new opportunities for gene-specific inhibition and knockdown, as well as new ideas for the treatment of disease. Four siRNA drugs have already been approved for marketing. However, the instability of siRNA in vivo makes systemic delivery ineffective. Inhaled siRNA formulations can deliver drugs directly to the lung, showing great potential for treating respiratory diseases. The clinical applications of inhaled siRNA formulations still face challenges because effective delivery of siRNA to the lung requires overcoming the pulmonary and cellular barriers. This paper reviews the research progress for siRNA inhalation formulations for the treatment of various respiratory diseases and summarizes the chemical structural modifications and the various delivery systems for siRNA. Finally, we conclude the latest clinical application research for inhaled siRNA formulations and discuss the potential difficulty in efficient clinical application.

Targeted Strategy in Lipid-Lowering Therapy

Dyslipidemia is characterized by a diminished lipid profile, including increased level of total cholesterol and low-density lipoprotein cholesterol (LDL-c) and reduced level of high-density lipoprotein cholesterol (HDL-c). Lipid-lowering agents represent an efficient tool for the prevention or reduction of progression of atherosclerosis, coronary heart diseases and metabolic syndrome. Statins, ezetimibe, and recently proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are the most effective and used drugs in clinical lipid-lowering therapy. These drugs are mainly aimed to lower cholesterol levels by different mechanisms of actions. Statins, the agents of the first-line therapy—known as 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitors—suppress the liver cholesterol synthesis. Ezetimibe as the second-line therapy can decrease cholesterol by inhibiting cholesterol absorption. Finally, the PCSK9 inhibitors act as an inducer of LDL excretion. In spite of their beneficial lipid-lowering properties, many patients suffer from their serious side effects, route of administration, or unsatisfactory physicochemical characteristics. Clinical demand for dose reduction and the improvement of bioavailability as well as pharmacodynamic and pharmacokinetic profile has resulted in the development of a new targeted therapy that includes nanoparticle carriers, emulsions or vaccination often associated with another more subtle form of administration. Targeted therapy aims to exert a more potent drug profile with lipid-lowering properties either alone or in mutual combination to potentiate their beneficial effects. This review describes the most effective lipid-lowering drugs, their favorable and adverse effects, as well as targeted therapy and alternative treatments to help reduce or prevent atherosclerotic processes and cardiovascular events.

Cholesterol Lowering Biotechnological Strategies: From Monoclonal Antibodies to Antisense Therapies. A Pre-Clinical Perspective Review

In recent years, the increase in available genetic information and a better understanding of the genetic bases of dyslipidemias has led to the identification of potential new avenues for therapies. Additionally, the development of new technologies has presented the key for developing novel therapeutic strategies targeting not only proteins (e.g., the monoclonal antibodies and vaccines) but also the transcripts (from antisense oligonucleotides (ASOs) to small interfering RNAs) or the genomic sequence (gene therapies). These pharmacological advances have led to successful therapeutic improvements, particularly in the cardiovascular arena because we are now able to treat rare, genetically driven, and previously untreatable conditions (e.g, familial hypertriglyceridemia or hyperchylomicronemia). In this review, the pre-clinical pharmacological development of the major biotechnological cholesterol lowering advances were discussed, describing facts, gaps, potential future steps forward, and therapeutic opportunities.

PCSK9 Inhibitor Wars: How Does Inclisiran Fit in with Current Monoclonal Antibody Inhibitor Therapy? Considerations for Patient Selection

PURPOSE OF REVIEW

Treatment of dyslipidemia represents one of the most crucial strategies to reduce risk of atherosclerotic cardiovascular (CV) disease (ASCVD). In this review, we critically summarize our knowledge on emerging cholesterol-lowering therapy, targeting PCSK9, paying particular attention on treatment allocation of two drug groups, currently available for clinical use, namely, anti-PCSK9 monoclonal antibodies (mAbs) and inclisiran, a first-in-class small interfering RNA against PCSK9.

RECENT FINDINGS

Although both drug classes show a pronounced, but fairly similar reduction in LDL-cholesterol, their long-term safety is still unknown. Compared to mAbs, inclisiran has a more favorable dosing regimen with biannual application that might improve therapeutic adherence significantly. However, a CV outcome trial (CVOT) for inclisiran is still missing. If inclisiran will be safe and effective in ongoing/future CVOTs, it has a huge potential to overcome medication non-compliance, thereby providing a powerful therapeutic option to decrease the burden of ASCVD.

Apolipoprotein B and Cardiovascular Disease: Biomarker and Potential Therapeutic Target

Apolipoprotein (apo) B, the critical structural protein of the atherogenic lipoproteins, has two major isoforms: apoB48 and apoB100. ApoB48 is found in chylomicrons and chylomicron remnants with one apoB48 molecule per chylomicron particle. Similarly, a single apoB100 molecule is contained per particle of very-low-density lipoprotein (VLDL), intermediate density lipoprotein, LDL and lipoprotein(a). This unique one apoB per particle ratio makes plasma apoB concentration a direct measure of the number of circulating atherogenic lipoproteins. ApoB levels indicate the atherogenic particle concentration independent of the particle cholesterol content, which is variable. While LDL, the major cholesterol-carrying serum lipoprotein, is the primary therapeutic target for management and prevention of atherosclerotic cardiovascular disease, there is strong evidence that apoB is a more accurate indicator of cardiovascular risk than either total cholesterol or LDL cholesterol. This review examines multiple aspects of apoB structure and function, with a focus on the controversy over use of apoB as a therapeutic target in clinical practice. Ongoing coronary artery disease residual risk, despite lipid-lowering treatment, has left patients and clinicians with unsatisfactory options for monitoring cardiovascular health. At the present time, the substitution of apoB for LDL-C in cardiovascular disease prevention guidelines has been deemed unjustified, but discussions continue.

Acanthaster planci Inhibits PCSK9 and Lowers Cholesterol Levels in Rats

Atherosclerosis is the main cause of cardiovascular diseases which in turn, lead to the highest number of mortalities globally. This pathophysiological condition is developed due to a constant elevated level of plasma cholesterols. Statin is currently the widely used treatment in reducing the level of cholesterols, however, it may cause adverse side effects. Therefore, there is an urgent need to search for new alternative treatment. PCSK9 is an enzyme responsible in directing LDL-receptor (LDL-R)/LDL-cholesterols (LDL-C) complex to lysosomal degradation, preventing the receptor from recycling back to the surface of liver cells. Therefore, PCSK9 offers a potential target to search for small molecule inhibitors which inhibit the function of this enzyme. In this study, a marine invertebrate Acanthaster planci, was used to investigate its potential in inhibiting PCSK9 and lowering the levels of cholesterols. Cytotoxicity activity of A. planci on human liver HepG2 cells was carried out using the MTS assay. It was found that methanolic extract and fractions did not exhibit cytotoxicity effect on HepG2 cell line with IC50 values of more than 30 µg/mL. A compound deoxythymidine also did not exert any cytotoxicity activity with IC50 value of more than 4 µg/mL. Transient transfection and luciferase assay were conducted to determine the effects of A. planci on the transcriptional activity of PCSK9 promoter. Methanolic extract and Fraction 2 (EF2) produced the lowest reduction in PCSK9 promoter activity to 70 and 20% of control at 12.5 and 6.25 μg/mL, respectively. In addition, deoxythymidine also decreased PCSK9 promoter activity to the lowest level of 60% control at 3.13 μM. An in vivo study using Sprague Dawley rats demonstrated that 50 and 100 mg/kg of A. planci methanolic extract reduced the total cholesterols and LDL-C levels to almost similar levels of untreated controls. The level of serum glutamate oxalate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) showed that the administration of the extract did not produce any toxicity effect and cause any damage to rat liver. The results strongly indicate that A. planci produced a significant inhibitory activity on PCSK9 gene expression in HepG2 cells which may be responsible for inducing the uptake of cholesterols by liver, thus, reducing the circulating levels of total cholesterols and LDL-C. Interestingly, A. planci also did show any adverse hepato-cytotoxicity and toxic effects on liver. Thus, this study strongly suggests that A. planci has a vast potential to be further developed as a new class of therapeutic agent in lowering the blood cholesterols and reducing the progression of atherosclerosis.