Association of circulating PCSK9 concentration with cardiovascular metabolic markers and outcomes in stable coronary artery disease patients with or without diabetes: a prospective, observational cohort study

Association between Apo B, LDL-R and PCSK9 gene polymorphisms with coronary artery diseases in Egyptians

BACKGROUND

Many studies have focused on the significance of lipid regulatory genes in the pathophysiology of Coronary artery disease (CAD). ApoB XbaI (rs693) and EcoRI (rs1042031) single nucleoid polymorphisms (SNPs) were investigated to detect whether they are risk factors for CAD. Till now, this association remains uncertain. SMARCA4 (rs1122608) SNP has directly related to dyslipidemia. Loss of function mutations (LOF) in PCSK9 result in a reduction in LDL cholesterol and are associated with protection from the development of CAD.

METHODS

This study was conducted on 54 CAD patients who were admitted at Internal Medicine Specialized Hospital (Cardiology Department) and 47 healthy controls. Peripheral blood samples were taken from both groups. DNA was extracted from EDTA-blood samples, then PCR- RFLP for ApoB XbaI (rs693) and EcoRI (rs1042031), SMARCA4 (rs1122608) and PCSK9 (rs505151) SNPs was done.

RESULTS

No statistically significant difference was found between patients and controls as regard EcoRI SNP. XbaI (rs693) X + X + genotype was significantly higher in control group (P = 0.0355). SMARCA4 (TT, GT + TT) genotypes, and T allele (P < 0.001); PCSK9 AG genotype and G allele (P = 0.027 and 0.032 respectively) were more frequent in CAD patients than controls.

CONCLUSION

SMARCA4 (rs1122608) and PCSK9 (rs505151) SNPs are significantly accompanying with the risk of CAD development in the Egyptian population. X + X + genotype appeared to have a protective effect against CAD. However, no observed association between EcoRI (rs1042031) and the risk of CAD development was found.

PCSK9 inhibitors: a patent review 2018-2023

INTRODUCTION

Proprotein convertase subtilisin/kexin 9 (PCSK9) plays a crucial role in breaking down the hepatic low-density lipoprotein receptor (LDLR), thereby influencing the levels of circulating low-density lipoprotein cholesterol (LDL-C). Consequently, inhibiting PCSK9 through suitable ligands has been established as a validated therapeutic strategy for combating hypercholesterolemia and cardiovascular diseases.

AREA COVERED

Patent literature claiming novel compounds inhibiting PCSK9 disclosed from 2018 to June 2023 available in the espacenet database, which contains more than 150 million patent documents from over 100 patent-granting authorities worldwide.

EXPERT OPINION

The undisputable beneficial influence of PCSK9 as a pharmacological target has prompted numerous private and public institutions to patent chemical frameworks as inhibitors of PCSK9. While several compounds have advanced to clinical trials for treating hypercholesterolemia, they have not completed these trials yet. These compounds must contend in a complex market where new, costly, and advanced drugs, such as monoclonal antibodies and siRNA, are prescribed instead of inexpensive and less potent statins.

Targeted Proteomics Reveals Functional Targets for Early Diabetes Susceptibility in Young Adults

BACKGROUND

The circulating proteome may encode early pathways of diabetes susceptibility in young adults for surveillance and intervention. Here, we define proteomic correlates of tissue phenotypes and diabetes in young adults.

METHODS

We used penalized models and principal components analysis to generate parsimonious proteomic signatures of diabetes susceptibility based on phenotypes and on diabetes diagnosis across 184 proteins in >2000 young adults in the CARDIA (Coronary Artery Risk Development in Young Adults study; mean age, 32 years; 44% women; 43% Black; mean body mass index, 25.6±4.9 kg/m2), with validation against diabetes in >1800 individuals in the FHS (Framingham Heart Study) and WHI (Women's Health Initiative).

RESULTS

In 184 proteins in >2000 young adults in CARDIA, we identified 2 proteotypes of diabetes susceptibility-a proinflammatory fat proteotype (visceral fat, liver fat, inflammatory biomarkers) and a muscularity proteotype (muscle mass), linked to diabetes in CARDIA and WHI/FHS. These proteotypes specified broad mechanisms of early diabetes pathogenesis, including transorgan communication, hepatic and skeletal muscle stress responses, vascular inflammation and hemostasis, fibrosis, and renal injury. Using human adipose tissue single cell/nuclear RNA-seq, we demonstrate expression at transcriptional level for implicated proteins across adipocytes and nonadipocyte cell types (eg, fibroadipogenic precursors, immune and vascular cells). Using functional assays in human adipose tissue, we demonstrate the association of expression of genes encoding these implicated proteins with adipose tissue metabolism, inflammation, and insulin resistance.

CONCLUSIONS

A multifaceted discovery effort uniting proteomics, underlying clinical susceptibility phenotypes, and tissue expression patterns may uncover potentially novel functional biomarkers of early diabetes susceptibility in young adults for future mechanistic evaluation.

E670G PCSK9 polymorphism in HeFH & CAD with diabetes: is the bridge to personalized therapy within reach?

Objective

To assess the distribution of PCSK9 E670G genetic polymorphism and PCSK9 levels in patients with Coronary Artery Disease (CAD) and Heterozygous Familial Hypercholesterolemia (HeFH), based on the presence of type 2 Diabetes Mellitus (T2DM).

Methods

The study included 201 patients with chronic CAD, including those with HeFH (n=57, group I) and without it (n=144, group II). DLCN was used to diagnose HeFH. The PCSK9 E670G (rs505151) polymorphism was genetically typed using the PCR-RFLP procedure. In both the patient and control groups, the genotype frequency matched the Hardy-Weinberg equilibrium distribution (P>0.05).

Results

There were twice more G alleles in group I (13, 11.4%) than in group II (17, 6.0%), and thrice more (1, 3.0%) than in the healthy control group; nevertheless, these differences weren't statistically significant. Simultaneously, PCSK9 levels were higher in HeFH patients (P<0.05) compared to non-HeFH patients not taking statins (n=63). T2DM was equally represented in groups I and II (31.6% vs. 33.3%). But carriers of AG+GG genotypes in group I had a higher chance of having a history of T2DM (RR 4.18; 95%CI 2.19-8.0; P<0.001), myocardial infarction (RR 1.79; 95%CI 1.18-2.73; P<0.05), and revascularization (RR 12.6; 95%CI 4.06-38.8; P<0.01), than AA carriers. T2DM was also more common among G allele carriers (RR 1.85; 95% CI 1.11-3.06; P<0.05) in patients with non-HeFH.

Conclusion

T2DM in patients with CAD, both with HeFH and non-HeFH, in the Uzbek population was significantly more often associated with the presence of the "gain-of-function" G allele of the PCSK9 E670G genetic polymorphism.

Elevated circulating PCSK9 level is associated with 28-day mortality in patients with sepsis: a prospective cohort study

OBJECTIVES

Pro-protein convertase subtilisin/kexin 9 (PCSK9) decreases the clearance of the pathogenic lipids, supporting the potential role of PCSK9 in the prognosis of sepsis.

METHODS

In this prospective cohort study, patients with sepsis were consecutively recruited from 1 to 2020 to 30 September 2021 at the First People's Hospital of Huaihua, China. All the eligible patients were categorized into low-PCSK9 and high-PCSK9 groups, based on their PCSK9 levels at admission. Time-dependent receiver operating characteristic curves and Cox proportional hazards regression were used to evaluate the association between PCSK9 level and 28-day mortality of sepsis.

RESULTS

Of the 203 enrolled patients, 56 (27.59%) died during the 28-day follow-up. The PCSK9 level was positively related to the C-reactive protein level. The cut-off point of PCSK9 levels for 28-day mortality risk was 370 ng/ml. Through comparison between high-PCSK9 (> 370 ng/ml) with low-PCSK9 (≤ 370 ng/ml) groups, the adjusted HR for mortality was 2.56 (95% CI: 1.25-5.23, p = 0.01).

CONCLUSIONS

The 28-day mortality of sepsis increased significantly as the baseline circulating PCSK9 level exceeded 370 ng/ml, indicating circulating PCSK9 levels may be a potential biomarker to predict the prognosis of sepsis.

Identification and validation of PCSK9 as a prognostic and immune-related influencing factor in tumorigenesis: a pan-cancer analysis

Introduction

Proprotein convertase subtilisin/kexin-9 (PCSK9) has been primarily studied in the cardiovascular field however, its role in cancer pathophysiology remains incompletely defined. Recently, a pivotal role for PCSK9 in cancer immunotherapy was proposed based on the finding that PCSK9 inhibition was associated with enhancing the antigen presentation efficacy of target programmed cell death-1 (PD-1). Herein, we provide results of a comprehensive pan-cancer analysis of PCSK9 that assessed its prognostic and immunological functions in cancer.

Methods

Using a variety of available online cancer-related databases including TIMER, cBioPortal, and GEPIA, we identified the abnormal expression of PCSK9 and its potential clinical associations in diverse cancer types including liver, brain and lung. We also validated its role in progression-free survival (PFS) and immune infiltration in neuroblastoma.

Results

Overall, the pan-cancer survival analysis revealed an association between dysregulated PCSK9 and poor clinical outcomes in various cancer types. Specifically, PCSK9 was extensively genetically altered across most cancer types and was consistently found in different tumor types and substages when compared with adjacent normal tissues. Thus, aberrant DNA methylation may be responsible for PCSK9 expression in many cancer types. Focusing on liver hepatocellular carcinoma (LIHC), we found that PCSK9 expression correlated with clinicopathological characteristics following stratified prognostic analyses. PCSK9 expression was significantly associated with immune infiltrate since specific markers of CD8+ T cells, macrophage polarization, and exhausted T cells exhibited different PCSK9-related immune infiltration patterns in LIHC and lung squamous cell carcinoma. In addition, PCSK9 was connected with resistance of drugs such as erlotinib and docetaxel. Finally, we validated PCSK9 expression in clinical neuroblastoma samples and concluded that PCSK9 appeared to correlate with a poor PFS and natural killer cell infiltration in neuroblastoma patients.

Conclusion

PCSK9 could serve as a robust prognostic pan-cancer biomarker given its correlation with immune infiltrates in different cancer types, thus potentially highlighting a new direction for targeted clinical therapy of cancers.

Protective effect of evolocumab on Müller cells in the rat retina under hyperglycaemic and hypoxic conditions

AIMS

In this study, rat retinal Müller cells (RMCs) were cultured in vitro to investigate the protective mechanism of evolocumab on rat RMCs in diabetes mellitus (DM) and the expression of relevant inflammatory factors.

METHODS

The expression of proprotein convertase subtilisin/kexin type 9 (PCSK9) in the retinal tissues of diabetic rats was detected by immunohistochemistry. Sprague-Dawley (SD) rats at 5-7 d of life were selected as the source of RMCs and divided equally into three groups of 12 rats/24 eyes each. The effect of CoCl2 and evolocumab on the cellular activity of RMCs was determined by CCK-8 assay. The effect of CoCl2 and evolocumab on the migration level of RMCs after 72 h was measured by scratch test and the expression of various proteins after 72 h was measured by Western blot.

RESULTS

In STZ rats, the expression of PCSK9 was significantly upregulated in the retina, especially in the inner nuclear layer, which is mainly composed of RMCs. High glucose and CoCl2 stimulation markedly elevated PCSK9 and GFAP expression at the protein level in RMCs (P < 0.05). Evolocumab treatment (100 μg/ml) reduced the expression and secretion of inflammatory factors in stimulated RMCs (P < 0.05). Furthermore, evolocumab downregulates toll-like receptor-4 (TLR-4) levels and inhibited nuclear transcription factor-κB (NF-κB) phosphorylation in RMCs (P < 0.05).

CONCLUSIONS

Evolocumab protects against inflammation in RMCs, at least in part, by negatively regulating the activation of the TLR-4/NF-κB signalling pathway. Evolocumab may be a promising anti-inflammatory therapy for ocular fundus diseases, such as DR.

PCSK9 causes inflammation and cGAS/STING pathway activation in diabetic nephropathy

Our previous research revealed that an increase in PCSK9 is linked to aggravated inflammation in the kidneys of mice affected by a high-fat diet and streptozotocin (HFD/STZ) or in HGPA-induced HK-2 cells. Furthermore, the cGAS/STING pathway has been reported to be involved in diabetic nephropathy (DN). Therefore, in this study, we aimed to examine the correlation between the proinflammatory effect of PCSK9 and the cGAS/STING pathway in DN. We used PCSK9 mAbs to inhibit PCSK9 in vivo and PCSK9 siRNA in vitro and measured the inflammatory phenotype in HFD/STZ-treated mice or HGPA-induced HK-2 cells, and observed decreased blood urea nitrogen, creatinine, UACR, and kidney injury in response to the PCSK9 mAb in HFD/STZ-treated mice. Moreover, IL-1 β, MCP-1, and TNF-α levels were reduced by the PCSK9 mAb in vivo and PCSK9 siRNA in vitro. We observed increased mtDNA damage and activation of the cGAS-STING signaling pathway during DN, as well as the downstream targets p-TBK1, p-NF-κB p65, and IL-1β. In a further experiment with an HGPA-induced DN model in HK-2 cells, we revealed that mtDNA damage was increased, which led to the activation of the cGAS/STING system and its downstream targets. Notably, the cGAS-STING signaling pathway was inhibited by the PCSK9 mAb in vivo and PCSK9 siRNA in vitro. In addition, inhibition of STING with C-176 in HGPA-induced HK-2 cells markedly blocked inflammation. In conclusion, we report for the first time that PCSK9 triggers mitochondrial DNA damage and activates the cGAS-STING pathway in DN, which leads to a series of inflammation cascades. PCSK9-targeted intervention can effectively reduce DN inflammation and delay its progression. Moreover, the inhibition of STING significantly abrogated the inflammation triggered by HGPA in HK-2 cells.

The Anti-Thrombotic Effects of PCSK9 Inhibitors

Atherosclerosis is the primary process that underlies cardiovascular disease. The connection between LDL cholesterol and the formation of atherosclerotic plaques is established by solid evidence. PCSK9 inhibitors have proven to be a valuable and practical resource for lowering the LDL cholesterol of many patients in recent years. Their inhibitory effect on atherosclerosis progression seems to be driven not just by lipid metabolism modification but also by LDL-independent mechanisms. We review the effect of PCSK9 inhibitors on various mechanisms involving platelet activation, inflammation, endothelial dysfunction, and the resultant clot formation. The main effectors of PCSK9 activation of platelets are CD36 receptors, lipoprotein(a), oxidised LDL particles, tissue factor, and factor VIII. Many more molecules are under investigation, and this area of research is growing rapidly.

Insight into the role of PCSK9 in glucose metabolism

Diabetes mellitus (DM) is strongly associated with an increased risk of atherosclerotic cardiovascular disease (ASCVD). Proprotein convertase subtilisin/kexin type 9 (PCSK9) was recently identified as an important regulator of circulating low-density lipoprotein-cholesterol (LDL-C) levels via degradation of the LDL receptor, proving to be a valid target to improve lipoprotein profiles and cardiovascular outcomes in patients with ASCVD. Beyond LDL receptor processing and cholesterol homeostasis, the PCSK9 protein has recently been verified to be associated with glucose metabolism. Importantly, clinical trials suggest that treatment with PCSK9 inhibitors for patients with DM is more effective. Hence, in this review, we summarize the current findings derived from experimental, preclinical, and clinical studies regarding the association between PCSK9 and glucose metabolism, including the relationship of PCSK9 genetic mutations to glucose metabolism and diabetes, the link between plasma PCSK9 concentrations and glucose metabolic parameters, the effects of glucose-lowering drugs on plasma PCSK9 levels and the impacts of PCSK9 inhibitors on cardiovascular outcomes of patients with DM. Clinically, exploring this field may improve our understanding regarding the roles of PCSK9 in glucose metabolism and may offer an in-depth interpretation of how PCSK9 inhibitors exert effects on the treatment of patients with DM.

Circulating Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) is Associated with Disease Activity and Risk of Incident Cardiovascular Disease in Patients with Systemic Lupus Erythematosus

To study the relationship of serum PCSK9 and disease activity and major adverse cardiovascular events (MACEs) in systemic lupus erythematosus (SLE). Consecutive patients who fulfilled ≥ 4 ACR criteria for SLE and consented for a biomarker study in 2009-2013 were included. Stored serum samples were assayed for PCSK9. PCSK9 levels were correlated with SLE disease activity scores. Patients were divided into two groups according to the median PCSK9 level and new MACEs over time were evaluated. The effect of PCSK9 level on MACEs and mortality was studied by Cox regression, adjusted for confounders. A total of 539 SLE patients were studied (93% women, age 41.9 ± 14.0 years). The median PCSK9 level at baseline was 220 ng/ml. Patients with higher PCSK9 (≥ 220 ng/ml; n = 269) had significantly higher SLE disease activity index (SLEDAI) than those with lower PCSK9 (< 220 ng/ml; n = 270). PCSK9 levels were significantly higher in patients with active renal than active non-renal SLE, which in turn were significantly higher than those with inactive SLE or healthy controls. PCSK9 level correlated with SLEDAI in the overall population (ρ = 0.30; p < 0.001). Over 91.3 ± 18.6 months, 29 patients developed 31 MACEs and 40 patients succumbed (25% for vascular events). The cumulative incidence of MACEs at 5 years was 4.8% in the higher PCSK9 and 1.1% in the lower PCSK9 group (HR2.51[1.11-5.70]; p = 0.03). Cox regression revealed higher PCSK9 was significantly associated with MACEs (HR1.003[1.000-1.005] per ng/ml; p = 0.02) independent of age, sex, renal function, baseline disease activity score, traditional atherosclerotic risk factors, antiphospholipid antibody and the use of aspirin/warfarin, statins and immunosuppressive drugs. PCSK9 level was also independently associated with all-cause (HR1.002[1.000-1.004] per ng/ml; p = 0.03) and vascular mortality (HR1.004[1.000-1.007]; p = 0.04). We concluded that serum PCSK9 level correlates with SLE disease activity. Higher serum PCSK9 levels are associated with increased risk of cardiovascular events and mortality in SLE.

Serum proprotein convertase subtilisin/Kexin type 9 and vascular disease in type 2 diabetic patients

BACKGROUND

Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) levels have been suggested as novel atherosclerotic biomarker. PCSK9 plays important roles in the pathogenesis of atherosclerosis by regulating the degradation of low-density lipoprotein receptor as well as different inflammatory pathways. Considering the important prognostic role of arterial stiffness in cardiovascular disease (CVD), the aim of the study is to investigate the correlation between PCSK9 levels and arterial stiffness in a cohort of diabetic patients, without previous CV events.

METHODS

This cross-sectional analysis enrolled 401 Caucasian patients with type II diabetes mellitus (T2DM). PCSK9 levels were measured by ELISA test, arterial stiffness was estimated by measuring carotid-femoral pulse wave velocity (PWV).

RESULTS

Patients were divided in three tertiles according to increasing value of PCSK9. From the I to the III tertiles, there was a significant increase in high sensitivity C-reactive protein (hs-CRP), fibrinogen and white blood cells (WBC) and a reduction in estimated glomerular filtration rate (e-GFR). Patients with higher levels of PCSK9 presented increased systolic, diastolic blood pressure, pulse pressure and PWV. PWV was significantly and directly correlated with PCSK9, fibrinogen, age, BMI and PP, and indirectly correlated with diet, lifestyle and e-GFR. Serum PCSK9 was the major predictor of PWV, justifying a 16.9% of its variation.

CONCLUSION

Our study demonstrates a close association between circulating PCSK9 levels and PWV in T2DM subjects without previous CV events even after adjusting for well-known CV risk factor and pharmacological medications. Serum PCSK9 could be a useful biomarker for CV risk stratification in diabetic subjects.

Effect of Triglyceride-Glucose Indices and Circulating PCSK9-Associated Cardiovascular Risk in STEMI Patients with Primary Percutaneous Coronary Artery Disease: A Prospective Cohort Study

Background and Aims

This study aimed to determine whether convertase subtilisin/kexin type 9 (PCSK9)-associated cardiovascular risk is modulated by triglyceride-glucose (TyG) in ST-segment elevation myocardial infarction (STEMI) patients with primary percutaneous coronary disease (PCI).

Methods

A total of 1541 patients with STEMI (aged ≥18 years) undergoing primary PCI were consecutively enrolled between March 2017 and March 2019.

Outcomes

When stratifying the overall population according to TyG indices less than or greater than the median (TyG median = 9.07) as well as according to quartiles of PCSK9 levels, higher TyG index levels were significantly associated with all-cause mortality only when TyG levels were 9.07 or higher (ie, relative to quartile 1 [Q1], the adjusted HR for all-cause mortality was 3.20 [95% CI, 0.54-18.80] for Q2, p = 0.199; 7.89 [95% CI, 1.56-40.89] for Q3, p = 0.013; and 5.61 [95% CI, 1.04-30.30] for Q4, p = 0.045. During a median follow-up period of 1.96 years, the HR for all-cause mortality was higher in the subset of patients with TyG ≥median and PCSK9 ≥median (p for trend = 0.023) among those with type 2 diabetes mellitus (T2DM). However, there were no statistically significant differences among the subgroups. Among T2DM patients with a TyG index greater than the median, the Kaplan-Meier curve showed that patients with the highest PCSK9 levels had an increased risk of all-cause mortality (log-rank p = 0.017) and cardiac-cause mortality (log-rank p = 0.037) compared with lower PCSK9 quartile levels.

Conclusion

Elevated PCSK9 levels are related to all-cause mortality and cardiac-related mortality when TyG levels are greater than the median, but not when levels are less than the median. This suggests a potential benefit of lowering circulating PCSK9 levels in STEMI patients with insulin resistance.

Serum Levels of PCSK9 Are Increased in Patients With Active Ulcerative Colitis Representing a Potential Biomarker of Disease Activity: A Cross-sectional Study

BACKGROUND/GOAL

Ulcerative colitis (UC) is characterized by chronic inflammation and progressive course, with potential extraintestinal complications including cardiovascular mortality. Serum proprotein convertase subtilisin/kexin type 9 (PCSK9) levels have been recently recognized as biomarkers of low-grade inflammation and cardiovascular disease. The aim of our study was to evaluate PCSK9 levels in patients with UC and different degrees of disease activity.

METHODS

We prospectively recruited consecutive patients with UC attending our center at the University Hospital of Padua. Demographics, clinical characteristics, and biochemical data, including PCSK9, high sensitivity C-reactive protein, and fecal calprotectin, were recorded. Moreover, endoscopic procedures were performed in all subjects.

RESULTS

We included 112 patients with UC (mean age=52.62±12.84 y; 52.62% males). Patients with UC and abnormal fecal calprotectin (≥250 µg/g) and/or C-reactive protein (≥3 mg/L) had greater levels of PCSK9 compared with UC patients with normal fecal calprotectin and high sensitivity C-reactive protein ( P =0.03 and 0.005, respectively). Higher endoscopic scores in UC were characterized by greater levels of PCSK9 ( P =0.03). Furthermore, we found a positive correlation between PCSK9 levels and fecal calprotectin ( r =0.18, P =0.04), endoscopic Mayo Score ( r =0.25, P =0.007), and UC-Riley Index ( r =0.22, P =0.01). We also found a positive correlation between PCSK9 levels and both total and low-density lipoprotein cholesterol values ( P <0.05).

CONCLUSIONS

Serum PCSK9 levels are increased in patients with biochemical and endoscopic evidence of active disease in UC. Further longitudinal studies are necessary to evaluate the role of PCSK9 as a potential biomarker of disease activity and cardiovascular risk in UC.

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.

Sex difference in circulating PCSK9 and its clinical implications

Proprotein convertase subtilisin kexin type 9 (PCSK9) is a proprotein convertase that increases plasma low-density lipoprotein cholesterol (LDL-C) levels by triggering the degradation of LDL receptors (LDLRs). Beyond the regulation of circulating LDL-C, PCSK9 also has direct atherosclerotic effects on the vascular wall and is associated with coronary plaque inflammation. Interestingly, emerging data show that women have higher circulating PCSK9 concentrations than men, suggesting that the potential roles of PCSK9 may have different impacts according to sex. In this review, we summarize the studies concerning sex difference in circulating levels of PCSK9. In addition, we report on the sex differences in the relations of elevated circulating PCSK9 levels to the severity and prognosis of coronary artery disease, the incidence of type 2 diabetes mellitus, and neurological damage after cardiac arrest and liver injury, as well as inflammatory biomarkers and high-density lipoprotein cholesterol (HDL-C). Moreover, sex difference in the clinical efficacy of PCSK9 inhibitors application are reviewed. Finally, the underlying mechanisms of sex difference in circulating PCSK9 concentrations and the clinical implications are also discussed.

Proprotein convertase subtilisin/kexin type 9 inhibitor non responses in an adult with a history of coronary revascularization: A case report

BACKGROUND

Familial hypercholesterolemia (FH) is an autosomal dominant disorder that is characterized by severely increased low-density lipoprotein (LDL) cholesterol levels. At the same time, elevated LDL levels accelerated the development of coronary heart disease. Several classes of drugs are currently in use to treat FH. Proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) is novel one of these.

CASE SUMMARY

This manuscript reports a case of FH that responded modestly after treatment with PCSK9i and statin drugs. Of even more concern is that the patient frequently admitted to the hospital during a 12-year follow-up period. Subsequently, we identified a heterozygous mutation, 1448G>A (W483X) of the LDL receptor (LDLR) in this patient. The serum levels of PCSK9 (proprotein convertase subtilisin/kexin type 9) in the patient was 71.30 ± 26.66 ng/mL, which is close the average level reported in the literature. This LDLR mutation affects LDLR metabolism or structure, which may make it unsuitable for use of PCSK9i.

CONCLUSION

Our outcome demonstrates that LDLR-W483X represents a partial loss-of-function LDLR and may contribute to PCSK9i ineffective. In the meanwhile, additional measures are therefore required (particularly with gene sequencing or change the treatment plan) must be initiated as early as possible. Genetic testing for clinically challenging cases who do not respond to PCSK9i therapy is very helpful.

Association of PCSK9 with inflammation and platelet activation markers and recurrent cardiovascular risks in STEMI patients undergoing primary PCI with or without diabetes

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been shown to be predictive of cardiovascular outcomes in stable coronary artery disease with diabetes. We aimed to assess the relationship between PCSK9 and major adverse cardiovascular events (MACEs) in ST-segment elevation myocardial infarction (STEMI) patients with or without diabetes, as well as the relationships between PCSK9 and metabolism, inflammation and platelet activation markers.

METHODS

A total of 1027 patients with STEMI undergoing primary percutaneous coronary intervention (PCI) and without prior lipid-lowering therapy were consecutively enrolled and the baseline plasma PCSK9 levels were determined by ELISA. Patients were divided into high and low PCSK9 groups according to PCSK9 median. All patients were followed up for the occurrence of MACEs. The associations of PCSK9 with metabolism, inflammation and platelet activation markers and MACEs were evaluated.

RESULTS

PCSK9 levels were positively correlated with triglycerides, high-sensitivity C reactive protein, soluble CD40 ligand and soluble P-selectin levels, and the correlations were stronger in diabetic patients than in non-diabetic patients. In diabetic patients receiving ticagrelor, PCSK9 levels were positively correlated with maximal platelet aggregation measured by light transmittance aggregometry and maximum amplitude of adenosine diphosphate-induced platelet-fibrin clots measured by thrombelastography in the maintenance phase of treatment, whereas no correlations were found in non-diabetic patients. During a median follow-up of 2.0 years, 155 (15.1%) MACEs occurred. The Kaplan-Meier analysis displayed that the patients with high PCSK9 levels had lower event-free survival rate than those with low PCSK9 levels (P = 0.030). When participants were categorized into 4 subgroups according to PCSK9 levels and diabetes status, high PCSK9 levels plus diabetes subgroup had the lowest cumulative event-free survival rate (P = 0.043). Multivariable Cox regression analysis revealed that high PCSK9 levels were independently associated with MACEs in diabetic patients (hazard ratio 2.283, 95% confidence interval: 1.094-4.764, P = 0.028), but not in the whole cohort or non-diabetic patients.

CONCLUSIONS

The study showed that high PCSK9 levels were independently associated with MACEs in STEMI patients with diabetes undergoing primary PCI, and the association may be due to stronger correlations of PCSK9 with inflammation and platelet activation markers in diabetic patients.

Effect of PCSK9 Inhibitors on Hemostasis in Patients with Isolated Hypercholesterolemia

Background: In addition to reducing plasma lipids, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors may produce numerous nonlipid-related pleiotropic effects. The purpose of this trial was to determine the efficacy of PCSK9 inhibitors alone in patients with isolated hypercholesterolemia. Methods: The trial enrolled 21 individuals with isolated hypercholesterolemia and atherosclerosis who received alirocumab for 90 days (150 mg every two weeks). Lipids, glucose homeostasis factors, and hemostatic markers were measured in the plasma at baseline and after treatment. Results: The PCSK9 inhibitor administered to these patients reduced plasma levels/activity of fibrinogen (from 3.6 ± 0.5 to 2.9 ± 0.4 g/L, p < 0.01), factor VII (from 143.8 ± 16.7 to 114.5 ± 14.1%, p < 0.01) and plasminogen activator inhibitor-1 (PAI-1) (from 74.9 ± 13.9 to 52.8 ± 9.1 ng/mL, p < 0.001) without a significant reduction in von Willebrand factor levels, and it tended to prolong the partial thromboplastin and prothrombin times. Conclusion: Our findings indicate that treatment with PCSK9 inhibitors has a multipotential effect on fibrinolysis and coagulation in patients with isolated hypercholesterolemia and that this medication may have some future benefits in patients who are statin-intolerant or contraindicated to statin use.

Association Between Circulating Proprotein Convertase Subtilisin/Kexin Type 9 Concentrations and Cardiovascular Events in Cardiovascular Disease: A Systemic Review and Meta-Analysis

Background: A large amount of evidence suggests that proprotein convertase subtilisin/Kexin type 9 (PCSK9) inhibitors have clinical benefits in patients with cardiovascular disease (CVD). However, whether PCSK9 concentrations predict future cardiovascular (CV) events remains unclear.

Methods: We conducted a meta-analysis to investigate the ability of PCSK9 concentrations to predict future CV events in patients with established CVD. A comprehensive search of electronic databases was conducted in June 2021. We included relative risk (RR) estimates with 95% CI or events of interest.

Results: Eleven cohort studies including 8,471 patients with CVD were enrolled. The pooled RR of CV events for the increase in the circulating baseline PCSK9 concentrations by 1 SD showed a positive association in a random-effect model (RR 1.226, 95% CI: 1.055–1.423, P = 0.008). Similarly, the risk of the total CV events increased by 52% in the patients in the highest tertile compared with those in the lowest tertile of circulating PCSK9 concentrations (RR 1.523, 95% CI: 1.098–2.112, P = 0.012). The association between PCSK9 and CV events was stronger in stable patients with CVD, patients treated with statins, and Asian patients.

Conclusions: High PCSK9 concentrations are significantly related to the increased risk of future CV events. These results enrich the knowledge of PCSK9 function and suggest the further possible clinical role of PCSK9 inhibitors.

Association of circulating proprotein convertase subtilisin/kexin type 9 concentration, prothrombin time and cardiovascular outcomes: a prospective cohort study

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is considered to have multiple roles in the development of atherosclerosis, which is recently reported to participate in the thrombotic process. We aimed to examine the relationship between PCSK9 concentration, coagulation indexes and cardiovascular events.

METHODS

A total of 2293 consecutive patients with angina-like chest pain and without lipid-lowering drugs treatment were enrolled and followed up for major adverse cardiovascular events (MACEs). Circulating PCSK9 concentration was determined by ELISA. The routine coagulation tests including activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time were performed. The associations between PCSK9 concentration, routine coagulation indicators and MACEs were analyzed.

RESULTS

Patients with high PCSK9 levels had lower PT and APTT levels (all p <  0.05). However, PCSK9 concentration was only independently and negatively correlated with PT (β = - 0.115, p <  0.001). During a mean of 38.3 months, 186 (8.1%) MACEs were occurred. Multiple Cox regression analysis indicated high PCSK9 or low PT levels as risk factors related to MACEs. When the prognosis was analyzed by the combination of PCSK9 and PT levels, patients with high PCSK9 and low PT had higher incidence of MACEs compared to those with low PCSK9 and high PT.

CONCLUSIONS

Our study firstly suggested that PCSK9 concentration was negatively correlated with plasma levels of PT. Furthermore, high PCSK9 and low PT were associated with MACEs and the combination of PCSK9 with PT had an addictive effect on predicting cardiovascular outcomes in patients with chest pain, which was useful for further subdivision of cardiovascular risks.

Circulating Biomarkers for Cardiovascular Disease Risk Prediction in Patients With Cardiovascular Disease

Cardiovascular disease (CVD) is the leading cause of death globally. Risk assessment is crucial for identifying at-risk individuals who require immediate attention as well as to guide the intensity of medical therapy to reduce subsequent risk of CVD. In the past decade, many risk prediction models have been proposed to estimate the risk of developing CVD. However, in patients with a history of CVD, the current models that based on traditional risk factors provide limited power in predicting recurrent cardiovascular events. Several biomarkers from different pathophysiological pathways have been identified to predict cardiovascular events, and the incorporation of biomarkers into risk assessment may contribute to enhance risk stratification in secondary prevention. This review focuses on biomarkers related to cardiovascular and metabolic diseases, including B-type natriuretic peptide, high-sensitivity cardiac troponin I, adiponectin, adipocyte fatty acid-binding protein, heart-type fatty acid-binding protein, lipocalin-2, fibroblast growth factor 19 and 21, retinol-binding protein 4, plasminogen activator inhibitor-1, 25-hydroxyvitamin D, and proprotein convertase subtilisin/kexin type 9, and discusses the potential utility of these biomarkers in cardiovascular risk prediction among patients with CVD. Many of these biomarkers have shown promise in improving risk prediction of CVD. Further research is needed to assess the validity of biomarker and whether the strategy for incorporating biomarker into clinical practice may help to optimize decision-making and therapeutic management.

Real-world data on metabolic effects of PCSK9 inhibitors in a tertiary care center in patients with and without diabetes mellitus

Background

The lipid-lowering and positive cardiovascular effect of proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors was shown in several studies, hence, they are more widely used in the lipid-lowering management of individuals with high cardiovascular risk. As real-world data are still scarce, specifically in patients with type 2 diabetes (T2D), the aim of this retrospective analysis was to investigate the efficacy of PCSK9 inhibitors in lowering low-density lipoprotein cholesterol (LDL-C) in an outpatient clinic of a tertiary care center in routine care.

Methods

A retrospective analysis of data extracted from the electronic patient record was performed. Patients who were routinely prescribed with PCSK9 inhibitor therapy (alirocumab or evolocumab) during the years 2016 and 2019 were included in the analysis. Characteristics of the patient population, the effects on LDL-C and HbA1c levels as well as subsequent cardiovascular events were assessed over an observation period of 18 months.

Results

We identified 237 patients treated with PCSK9 inhibitors between January 2016 and September 2019. Almost all patients (97.5%) received PCSK9 inhibitors for secondary prevention. 26.2% of the population had a concomitant diabetes diagnosis. Intolerance to statins (83.1%), ezetimibe (44.7%) or both agents (42.6%) was reported frequently. Three months after initiation of PCSK9 inhibitor therapy, 61.2% of the patients achieved LDL-C levels < 70 mg/dl, and 44.1% LDL-C levels < 55 mg/dl. The median LDL-C was lowered from 141 mg/dl at baseline, to 60 mg/dl after 3 months and 66 mg/dl after 12 months indicating a reduction of LDL-C as follows: 57.5% after 3 months and 53.6% after 12 months. After 3 months of observation, target achievement of LDL-C was higher in patients with T2D compared to non-diabetes patients; < 55 mg/dl: 51% vs. 41.5%; < 70 mg/dl 69.4 vs. 58.5%. After 12 months even more pronounced target LDL achievement in T2D was demonstrated < 55 mg/dl: 58.8% vs. 30.1%; < 70 mg/dl 70.6 vs. 49.6%. Patients with insufficiently controlled T2D (HbA1c > 54 mmol/mol) had a higher reduction in LDL-C but still were more likely to subsequent cardiovascular events.

Conclusions

Significant reductions in LDL-C and a high percentage of patients achieving recommended treatment targets were observed. The percentage of patients with T2D meeting recommended LDL-C targets was higher than in those without T2D. Still some patients did not achieve LDL-C levels as recommended in current guidelines. Special attention to the characteristics of these patients is required in the future to enable achievement of treatment goals and avoid adverse cardiovascular outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01283-w.

The predictive utility of circulating PCSK9 levels on diabetes mellitus

Increasing data including ours have suggested that proprotein convertase subtilisin/kexin type 9 (PCSK9), a novel regulator of cholesterol metabolism, may also play an important role in the development of type 2 diabetes mellitus (T2DM) and is associated with clinical outcomes in diabetic patients. Previous studies revealed that elevated plasma PCSK9 levels had a higher incidence of new-onset T2DM. Moreover, the results of available epidemiological, preclinical, and clinical studies have indicated that plasma PCSK9 concentration is correlated with glycemic parameters and can predict the adverse cardiovascular events in diabetic patients with coronary artery disease. However, there is currently no general agreement about the association of PCSK9 with T2DM. The usefulness of the circulating PCSK9 concentration as a predictor for the risk of new-onset T2DM should be clinically prudential.