Mature proprotein convertase subtilisin/kexin type 9, coronary atheroma burden, and vessel remodeling in heterozygous familial hypercholesterolemia

Relationship between Earlobe Crease and Anatomical Severity of Coronary Artery Disease in ST-segment Elevation Myocardial Infarction

Objective Earlobe crease (ELC) is an easily detectable physical sign of cardiovascular risk and coronary artery disease (CAD). However, the relationship between ELC and CAD severity in patients with ST-segment elevation myocardial infarction (STEMI) requiring urgent clinical judgment is unknown. Using the residual synergy between percutaneous coronary intervention with taxus and cardiac surgery (SYNTAX) score, we investigated the relationship between ELC and anatomical severity of CAD. Methods We studied 219 consecutive patients with STEMI (median age, 71 years old) and divided them into 2 groups according to the presence of ELC (ELC group, n=161; non-ELC group, n=58). Results The ELC group had a significantly higher number of diseased vessels than the non-ELC group (≥2 diseased vessels, 79% vs. 46%; ≥3 diseased vessels, 35% vs. 12%; p<0.001). In addition, a higher median residual SYNTAX score was observed after primary percutaneous coronary intervention than the non-ELC group [8 (4-12) vs. 3 (0-8), p<0.001]. Furthermore, a multivariable regression analysis showed that ELC was an independent predictor of the residual SYNTAX score (β=3.620, p<0.001). Conclusions The presence of ELC was significantly associated with the anatomical severity of diseased coronary vessels in patients with STEMI who required emergency clinical judgment and treatment.

The Role of Furin and Its Therapeutic Potential in Cardiovascular Disease Risk

Furin is an important proteolytic enzyme, converting several proteins from inactive precursors to their active forms. Recently, proteo-genomic analyses in European and East Asian populations suggested a causal association of furin with ischaemic heart disease, and there is growing interest in its role in cardiovascular disease (CVD) aetiology. In this narrative review, we present a critical appraisal of evidence from population studies to assess furin's role in CVD risk and potential as a drug target for CVD. Whilst most observational studies report positive associations between furin expression and CVD risk, some studies report opposing effects, which may reflect the complex biological roles of furin and its substrates. Genetic variation in FURIN is also associated with CVD and its risk factors. We found no evidence of current clinical development of furin as a drug target for CVD, although several phase 1 and 2 clinical trials of furin inhibitors as a type of cancer immunotherapy have been completed. The growing field of proteo-genomics in large-scale population studies may inform the future development of furin and other potential drug targets to improve the treatment and prevention of CVD.

Stratification in Heterozygous Familial Hypercholesterolemia: Imaging, Biomarkers, and Genetic Testing

PURPOSE OF REVIEW

Heterozygous familial hypercholesterolemia (HeFH) is the most common monogenic autosomal dominant disorder. However, the condition is often underdiagnosed and undertreated. The objective of this review is to provide an update on the risk stratification in patients with HeFH, incorporating new cardiovascular imaging techniques, various biomarkers, and genetic studies.

RECENT FINDINGS

The diagnosis of HeFH places patients in a high cardiovascular risk category due to the increased incidence of premature atherosclerotic cardiovascular disease. However, the level of risk varies significantly among different individuals with HeFH. Achieving an optimal stratification of cardiovascular risk is crucial for establishing appropriate and accurate treatment and management strategies. Different new tools such as risk scores have emerged in recent years, aiding physicians in assessing the risk stratification for HeFH using imaging, biomarkers, and genetics. This review emphasizes that not all patients with HeFH face the same cardiovascular risk. By utilizing different assessment tools, we can identify those who require more intensive monitoring, follow-up, and treatment.

Relationship between Serum Proprotein Convertase Subtilisin/Kexin Type 9 Concentration and Prevalence of Coronary Artery Calcium in a Community-Based Sample of Japanese Men

AIMS

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a promising new target for reducing low-density lipoprotein cholesterol (LDL-C) and cardiovascular events in high-risk patients. However, the influence of circulating PCSK9 concentration on atherosclerotic plaque formation in the general population remains unknown. We assessed the relationship between serum PCSK9 concentration and coronary artery calcium (CAC) prevalence in the general population.

METHODS

Community-dwelling Japanese men (n=622) aged 46-82 years without a history of cardiovascular disease and lipid-lowering medications were included. Serum PCSK9 concentration and CAC score were measured using the Agatston method, and the multivariable analysis was used to assess their association. CAC was defined as an Agatston score of ＞10. We conducted further analysis stratified by age (＜60, 60-69, and ≥ 70 years).

RESULTS

The average age, LDL-C, and median serum PCSK9 concentration were 68 years, 122 mg/dL, and 240 ng/mL, respectively. After multivariable adjustment for traditional cardiovascular risk factors, no significant association was observed between serum PCSK9 concentration and CAC prevalence (adjusted relative risk [aRR] 1.05, 95% confidence interval [CI] 0.97-1.13). With age stratification, serum PCSK9 concentration was significantly associated with CAC prevalence in men aged ＜60 years (aRR 1.38, 95% CI 1.01-1.88) but not in men aged 60-69 years (aRR 0.96, 95% CI 0.85-1.10) or ≥ 70 years (aRR 1.08, 95% CI 0.99-1.19).

CONCLUSIONS

A higher serum PCSK9 concentration was associated with a higher CAC prevalence in men aged ＜60 years, which was independent of traditional cardiovascular risk factors.

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.

Impact of conventional lipid-lowering therapy on circulating levels of PCSK9: protocol for a systematic review and meta-analysis of randomised controlled trials

INTRODUCTION

Conventional lipid-lowering agents, including statins, ezetimibe, fibrates, bile acid sequestrants, nicotinic acid, bempedoic acid and Omega-3, are essential to the management of dyslipidaemia. However, these agents have been shown to increase the level of plasma proprotein convertase subtilisin/kexin 9 (PCSK9), a serine protease associated with increased cardiovascular risk. This review aims to investigate the impact of commonly available conventional lipid-lowering agents on circulating PCSK9 levels and lipid profiles.

METHODS AND ANALYSIS

This protocol is conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines. A systematic search will be conducted in the following databases: MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, Web of Science, SCOPUS and ScienceDirect. Additional information will be retrieved from clinical trial registries or from reference list searches. Published and peer-reviewed randomised controlled trials with adults receiving statin, ezetimibe, fibrate, bile acid sequestrant, nicotinic acid, bempedoic acid or Omega-3 monotherapy or in combination for at least 2 weeks, with availability of plasma PCSK9 at the beginning and end of treatment or the net changes in values, will be included. Study selection, data extraction and assessment of the risk of bias will be independently conducted by two investigators. Continuous data will be presented as a standardised mean difference with 95% confidence interval (CI) and dichotomous data as risk ratios with 95% CI. Subgroup analysis and sensitivity analysis will be performed when sufficient studies are included. Publication bias will be assessed with a funnel plot and Egger's test.

ETHICS AND DISSEMINATION

Ethics approval is not required as this review will only include data from published sources. The results will be published in a peer-reviewed journal.

PATIENT AND PUBLIC INVOLVEMENT

No patient or members of the general public are involved.

PROSPERO REGISTRATION NUMBER

CRD42022297942.

How Can We Identify Very High-Risk Heterozygous Familial Hypercholesterolemia?

Heterozygous familial hypercholesterolemia (HeFH) is a genetic disorder that elevates low-density lipoprotein cholesterol and increases the risk of premature atherosclerotic cardiovascular disease (ASCVD). However, despite their atherogenic lipid profiles, the cardiovascular risk of HeFH varies in each individual. Their variety of phenotypic features suggests the need for better risk stratification to optimize their therapeutic management. The current review summarizes three potential approaches, including (1) definition of familial hypercholesterolemia (FH)-related risk scores, (2) genetic analysis, and (3) biomarkers. The International Atherosclerosis Society has recently proposed a definition of severe FH to identify very high-risk HeFH subjects according to their clinical characteristics. Furthermore, published studies have shown the association of FH-related genetic phenotypes with ASCVD, which indicates the genetic analysis's potential to evaluate individual cardiovascular risks. Biomarkers reflecting disease activity have been considered to predict the formation of atherosclerosis and the occurrence of ASCVD in HeFH subjects. Incorporating these risk stratifications will be expected to allocate adequate intensity of lipid-lowering therapies in HeFH subjects, which ultimately improves cardiovascular outcomes.

Circulating Mature PCSK9 Level Predicts Diminished Response to Statin Therapy

Background Statin-mediated efficacy of lowering low-density lipoprotein (LDL) cholesterol varies in each individual, and its diminished response is associated with worse outcomes. However, there is no established approach to predict hyporesponse to statins. PCSK9 (proprotein convertase subxilisin/kexin type 9) is a serine-protease associated with LDL metabolism, which circulates as mature and furin-cleaved PCSK9. Since mature PCSK9 more potently degrades the LDL receptor, its evaluation may enable the identification of statin hyporesponders. Methods and Results We analyzed 101 statin-naive patients with coronary artery disease who commenced a statin. PCSK9 subtypes at baseline and 1 month after statin use were measured by ELISA. Hyporesponse to statins was defined as a percent reduction in LDL cholesterol <15%. The relationship between each PCSK9 subtype level and hyporesponse to statins was investigated. Statins significantly lowered LDL cholesterol level (percent reduction, 40%±21%), whereas 11% of study participants exhibited a hyporeseponse to statins. Multivariable logistic regression analysis demonstrated that baseline mature PCSK9 level was an independent predictor for hyporesponse to statins even after adjusting clinical characteristics (mature PCSK9 per 10-ng/mL increase: odds ratio [OR], 1.12; 95% CI, 1.01-1.24 [P=0.03]), whereas furin-cleaved level was not (per 10-ng/mL increase: OR, 1.37; 95% CI, 0.73-2.58 [P=0.33]). Receiver operating characteristic curve analysis identified mature PCSK9 level of 228 ng/mL as an optimal cutoff to predict hyporesponse to statins (area under the curve, 0.73 [sensitivity, 0.91; specificity, 0.56]). Conclusions Baseline mature PCSK9 level >228 ng/mL is associated with hyporesponse to statins. This finding suggests that mature PCSK9 might be a potential determinant of hyporesponse to statins.

Plasma kinetics of mature PCSK9, furin-cleaved PCSK9, and Lp(a) with or without administration of PCSK9 inhibitors in acute myocardial infarction

BACKGROUND

There are two types of circulating proprotein convertase subtilisin/kexin type 9 (PCSK9), mature and furin-cleaved. Most types of lipoprotein(a) [Lp(a)], an independent risk factor of cardiovascular events, bind to mature PCSK9.

OBJECTIVE

This study examined the effects of monoclonal anti-PCSK9 antibody on plasma PCSK9 and Lp(a) levels in acute myocardial infarction (MI).

METHODS

Acute MI patients (n=36) were randomly divided into evolocumab (140mg; n=17) and non-evolocumab (n=19) groups. Changes in plasma PCSK9 and Lp(a) levels were monitored before and 1, 3, 5, 10, and 20 days after evolocumab administration.

RESULTS

In the non-evolocumab group, plasma levels of mature PCSK9, furin-cleaved PCSK9, and Lp(a) (236.4±57.3ng/mL, 22.4±5.8ng/mL, and 19.2.±16.5mg/dL, respectively) significantly increased by day 3 (408.8±77.1ng/mL, p<0.001; 47.2±15.7ng/mL, p<0.001; and 39.7±21.3mg/dL, p<0.005, respectively) and returned to the baseline by day 10 or 20. In the evolocumab group, mature PCSK9 significantly increased by >1000ng/mL with a simultaneous decline of furin-cleaved PCSK9 below the measurement sensitivity level after day 3. The incremental area under the curve for plasma Lp(a) levels was significantly smaller in the evolocumab group compared with the non-evolocumab group (p=0.038).

CONCLUSION

Mature and furin-cleaved PCSK9 are transiently upregulated after MI onset. Evolocumab significantly increases mature PCSK9 and decreases furin-cleaved PCSK9 and might inhibit transient increase of plasma Lp(a) in acute MI.

Genetics, Dyslipidemia, and Cardiovascular Disease: New Insights

PURPOSE OF REVIEW

The cardiovascular (CV) risk related to lipid disorders is well established and is based on a robust body of evidence from well-designed randomized clinical trials, as well as prospective observational studies. In the last two decades, significant advances have been made in understanding the genetic basis of dyslipidemias. The present review is intended as a comprehensive discussion of current knowledge about the genetics and pathophysiology of disorders that predispose to dyslipidemia. We also focus on issues related to statins and the proprotein convertase subtilisin/kexin type 9 (PCSK9) and some of its polymorphisms, as well as new cholesterol-lowering medications, including PCSK9 inhibitors.

RECENT FINDING

Cholesterol is essential for the proper functioning of several body systems. However, dyslipidemia-especially elevated low-density lipoprotein (LDL-c) and triglyceride levels, as well as reduced lipoprotein lipase activity-is associated with an increased risk of coronary artery disease (CAD). High-density lipoprotein (HDL-c), however, seems to play a role as a risk marker rather than as a causal factor of the disease, as suggested by Mendelian randomization studies. Several polymorphisms in the lipoprotein lipase locus have been described and are associated with variations in the activity of this enzyme, producing high concentrations of triglycerides and increased risk of CAD. Dyslipidemia, especially increased LDL-c and triglyceride levels, continues to play a significant role in CV risk. The combination of genetic testing and counseling is important in the management of patients with dyslipidemia of genetic etiology. Strategies focused on primary prevention can offer an opportunity to reduce CV events.

Pragmatic Analysis of Dyslipidemia Involvement in Coronary Artery Disease: A Narrative Review

Background

Dyslipidemia is the main factor involved in the occurrence and progression of coronary artery disease.

Objective

The research strategy is aimed at analyzing new data on the pathophysiology of dyslipidemia involvement in coronary artery disease, the modalities of atherogenic risk estimation and therapeutic advances.

Methods

Scientific articles published in PubMed from January 2017 to February 2018 were searched using the terms “dyslipidemia” and “ischemic heart disease”.

Results

PCSK9 contributes to the increase in serum levels of low-density lipoprotein-cholesterol and lipoprotein (a). The inflammation is involved in the progression of hyperlipidemia and atherosclerosis. Hypercholesterolemia changes the global cardiac gene expression profile and is thus involved in the increase of oxidative stress, mitochondrial dysfunction, and apoptosis initiated by inflammation. Coronary artery calcifications may estimate the risk of coronary events. The cardio-ankle vascular index evaluates the arterial stiffness and correlates with subclinical coronary atherosclerosis. The carotid plaque score is superior to carotid intima-media thickness for risk stratification in patients with familial hypercholesterolemia and both can independently predict coronary artery disease. The lipoprotein (a) and familial hypercholesterolemia have a synergistic role in predicting the risk of early onset and severity of coronary atherosclerosis. A decrease in atherosclerotic coronary plaque progression can be achieved in patients with plasma LDL-cholesterol levels below 70 mg/dL. A highly durable RNA interference therapeutic inhibitor of PCSK9 synthesis could be a future solution.

Conclusion

The prophylaxis and treatment of coronary artery disease in a dyslipidemic patient should be based on a careful assessment of cardio-vascular risk factors and individual metabolic particularities, so it may be personalized.