The significance of PCSK-9's level and polymorphism in premature coronary artery disease: Relation to risk and severity

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (PCSK-9) is a circulating protein that plays an important role in lipid metabolism and is linked to inflammation, which has implications for atherosclerosis and its severe cardiac effects. We studied the potential association of the PCSK-9 gene single nucleotide polymorphism (SNP), Oxidized low-density lipoprotein receptor 1- (OLR-1), and caspase-3 serum levels with the risk and severity of premature coronary artery disease (PCAD). The potential contribution of PCSK-9 serum level to the severity of PCAD patients was also assessed.

METHOD

This case-control study included 120 PCAD patients (age < 45), and 60 age matched healthy controls. Serum PCSK-9 and caspase-3 levels and clinical characteristics were recorded. SYNTAX score was calculated to estimate the severity of the coronary artery lesions. The SNP rs2483205 of the PCSK-9 gene and the rs11053646 of the OLR-1gene were genotyped in all participants.

RESULTS

Serum PCSK-9 levels were higher in PCAD patients and were significantly different among the three SYNTAX score groups (SS ≤ 12, 12 < SS ≤ 21.5, and SS > 21.5). The diagnostic cutoff values of PCSK-9 and caspase-3 levels for PCAD were > 3.2 ng/mL for both, yielding an area under the curve (AUC) of 0.98 and 0.92, sensitivity of 85 %, 98 %, and specificity of 99.5 %, 93 % for PCSK-9 and caspase-3, respectively. The genotypes TT + CT vs. CC of PCSK-9's rs2483205 SNP presented a higher risk for PCAD and higher SYNTAX scores. Furthermore, the rs11053646 SNP of OLR-1 presented the CG genotype as more risky and having higher SYNTAX scores.

CONCLUSION

Circulating PCSK9 and caspase-3 concentrations were higher in PCAD patients and were associated with CAD severity. The SNPs of PCSK-9 (rs2483205) and OLR-1 (rs11053646) were associated with PCAD and its severity.

PCSK9 regulates myofibroblast transformation through the JAK2/STAT3 pathway to regulate fibrosis after myocardial infarction

Cardiac fibrosis is pivotal in the progression of numerous cardiovascular diseases. This phenomenon is hallmarked by an excessive deposition of ECM protein secreted by myofibroblasts, leading to increased myocardial stiffness. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease that belongs to the proprotein-converting enzyme family. It has emerged as a viable therapeutic target for reducing plasma low-density lipoprotein cholesterol. However, the exact mechanism via which PCSK9 impacts cardiac fibrosis remains unclear. In the present research, an increase in circulating PCSK9 protein levels was observed in individuals with myocardial infarction and rat models of myocardial infarction. Moreover, the inhibition of circulating PCSK9 in rats was found to reduce post-infarction fibrosis. In vitro experiments further demonstrated that overexpression of PCSK9 or stimulation by extracellular PCSK9 recombinant protein enhanced the transformation of cardiac fibroblasts to myofibroblasts. This process also elevated collagen Ⅰ, and Ⅲ, as well as α-SMA protein levels. However, these effects were countered when co-incubated with the STAT3 inhibitor S3I-201. This study suggests that PCSK9 may function as a novel regulator of myocardial fibrosis, primarily via the JAK2/STAT3 pathway.

Longitudinal variation of serum PCSK9 in ulcerative colitis: association with disease activity, T helper 1/2/17 cells, and clinical response of tumor necrosis factor inhibitor

AIMS

Proprotein convertase subtilisin/kexin type 9 (PCSK9) modulates CD4+ T cell differentiation and inflammatory response, the latter ones mediate ulcerative colitis (UC) initiation. This study intended to explore the correlation of serum PCSK9 with disease activity, T helper (h)1/Th2/Th17 cells, and clinical response of tumor necrosis factor inhibitor (TNFi) in UC patients.

METHODS

In 65 UC patients underwent TNFi treatment, serum PCSK9 was evaluated at baseline (W0), week (W)2, W6, and W12 by enzyme-linked immunosorbent assays; meanwhile, Th1/Th2/Th17 cells were determined at W0 by flow cytometry. Besides, serum PCSK9 was detected in 65 healthy controls (HCs).

RESULTS

Serum PCSK9 was increased in UC patients compared to HCs (P<0.001), which also positively correlated with C-reactive protein (P=0.009), total Mayo score (P=0.018), Mayo-defined disease activity (P=0.020), Th1 (P=0.033), and Th17 (P=0.003) cells, but not Th2 cells (P=0.086) in UC patients. Interestingly, serum PCSK9 was steadily declined from W0 to W12 (P<0.001). W2-W0, W6-W0, and W12-W0 serum PCSK9 change (PCSK9 at W2, W6, or W12 minus PCSK9 at W0, respectively) was gradually becoming greater during TNFi treatment (P<0.001). Furthermore, forty-five (69.2%) patients achieved clinical response at W12, whose serum PCSK9 at W6 (P=0.041) and W12 (P=0.001) was lower, and W6-W0 (P=0.043), W12-W0 (P=0.019) serum PCSK9 change was more obvious compared to patients without clinical response at W12.

CONCLUSIONS

Serum PCSK9 is positively related to disease activity, Th1, and Th17 cells in UC patients; further, its decline correlates with TNFi response achievement in these patients.

Effect of PCSK9 inhibition on plasma levels of small dense low density lipoprotein-cholesterol and 7-ketocholesterol

BACKGROUND

Oxidized forms of cholesterol (oxysterols) are implicated in atherogenesis and can accumulate in the body via direct absorption from food or through oxidative reactions of endogenous cholesterol, inducing the formation of LDL particles loaded with oxidized cholesterol. It remains unknown whether drastic reductions in LDL-cholesterol (LDL-C) are associated with changes in circulating oxysterols and whether small dense LDL (sdLDL) are more likely to carry these oxysterols and susceptible to the effects of PCSK9 inhibition (PCSK9i).

OBJECTIVE

We investigate the effect of LDL-C reduction accomplished via PCSK9i on changes in plasma levels of sdLDL-cholesterol (sdLDL-C) and a common, stable oxysterol, 7-ketocholesterol (7-KC), among 134 patients referred to our Preventive Cardiology clinic.

METHODS

Plasma lipid panel, sdLDL-C, and 7-KC measurements were obtained from patients before and after initiation of PCSK9i.

RESULTS

The intervention caused a significant lowering of LDL-C (-55.4 %). The changes in sdLDL-C levels (mean reduction 51.4 %) were highly correlated with the reductions in LDL-C levels (R = 0.829, p < 0.001). Interestingly, whereas changes in plasma free 7-KC levels with PCSK9i treatment were much smaller than (-6.6 %) and did not parallel those of LDL-C and sdLDL-C levels, they did significantly correlate with changes in triglycerides and very low-density lipoprotein-cholesterol (VLDL-C) levels (R = 0.219, p = 0.025).

CONCLUSION

Our findings suggest a non-preferential clearance of LDL subparticles as a consequence of LDL receptor upregulation caused by PCSK9 inhibition. Moreover, the lack of significant reduction in 7-KC with PCSK9i suggests that 7-KC may be in part carried by VLDL and lost during lipoprotein processing leading to LDL formation.

Increased serum PCSK9 levels are associated with renal function impairment in patients with type 2 diabetes mellitus

PURPOSE

The purpose of this study was to investigate the association between serum proprotein convertase subtilisin/kexin type 9 (PCSK9) levels and renal function impairment in type 2 diabetes mellitus (T2DM) patients.

METHODS

PCSK9 levels were measured in T2DM patients, streptozotocin plus high-fat diet (STZ + HFD) mice, human proximal tubular epithelial (HK-2) cells treated with high glucose plus palmitic acid (HGPA) and the corresponding control groups. The T2DM patients were further divided into three groups according to serum PCSK9 levels. An analysis of clinical data was conducted, and a binary logistic regression model was used to test the relationship between potential predictors and urine albumin/urine creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR).

RESULTS

PCSK9 levels were higher in the DM group than in the control group in humans, mice and HK-2 cells. The systolic blood pressure (SBP), serum creatinine (Scr), blood urea nitrogen (BUN), triglyceride (TG), and urine α1-MG/urine creatinine ratio (UαCR) values in PCSK9 tertile 3 were significantly higher than those in PCSK9 tertile 1 (p < 0.05). The DBP and UACR values were significantly higher in PCSK9 tertile 3 than in PCSK9 tertile 1 and PCSK9 tertile 2 (both p < 0.05). In addition, URCR values were significantly higher in PCSK9 tertile 3 and PCSK9 tertile 2 than in PCSK9 tertile 1 (both p < 0.05). Serum PCSK9 levels were positively correlated with SBP, Scr, BUN, TG, URCR, UαCR and UACR but inversely correlated with eGFR. In STZ + HFD mice, serum PCSK9 levels were positively correlated with Scr, BUN and UACR, which was consistent with the findings in the patients. A logistic regression model revealed that serum PCSK9 is an independent risk factor for UACR ≥30 mg/g and eGFR <60 mL/min/1.73 m². The ROC curve showed that 170.53 ng/mL and 337.26 ng/mL PCSK9 were the best cutoff values for UACR ≥30 mg/g and eGFR <60 mL/min/1.73 m², respectively.

CONCLUSION

Serum PCSK9 levels are associated with renal function impairment in T2DM patients and in some patients lower PCSK9 may be helpful to decrease chronic kidney disease.

Anti-PCSK9 Treatment Attenuates Liver Fibrosis via Inhibiting Hypoxia-Induced Autophagy in Hepatocytes

Hypoxia and its induced autophagy are involved in the initiation and progression of liver fibrosis. Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been recognized as a potential regulator of autophagy. Our previously reported study found that PCSK9 expression increased in liver fibrosis and that anti-PCSK9 treatment alleviated liver injury. This study aimed to investigate the mechanism of anti-PCSK9 treatment on liver fibrosis by inhibiting hypoxia-induced autophagy. Carbon tetrachloride-induced mouse liver fibrosis and mouse hepatocyte line AML12, cultured under the hypoxic condition, were established to undergo PCSK9 inhibition. The degree of liver fibrosis was shown with histological staining. The reactive oxygen species (ROS) generation was detected by flow cytometry. The expression of PCSK9, hypoxia-inducible factor-1α (HIF-1α), and autophagy-related proteins was examined using Western blot. The autophagic flux was assessed under immunofluorescence and transmission electron microscope. The mouse liver samples were investigated via RNA-sequencing to explore the underlying signaling pathway. The results showed that PCSK9 expression was upregulated with the development of liver fibrosis, which was accompanied by enhanced autophagy. In vitro data verified that PCSK9 increased via hypoxia and inflammation, accompanied by the hypoxia-induced autophagy increased. Then, the validation was acquired of the bidirectional interaction of hypoxia-ROS and PCSK9. The hypoxia reversal attenuated PCSK9 expression and autophagy. Additionally, anti-PCSK9 treatment alleviated liver inflammation and fibrosis, reducing hypoxia and autophagy in vivo. In mechanism, the AMPK/mTOR/ULK1 signaling pathway was identified as a target for anti-PCSK9 therapy. In conclusion, anti-PCSK9 treatment could alleviate liver inflammation and fibrosis by regulating AMPK/mTOR/ULK1 signaling pathway to reduce hypoxia-induced autophagy in hepatocytes.

Clinical potential of inclisiran for patients with a high risk of atherosclerotic cardiovascular disease

Elevated low-density lipoprotein cholesterol (LDL-C) level is associated with an increased risk of atherosclerotic cardiovascular disease. Although high-intensity lipid-lowering therapies with statins and ezetimibe are highly effective for reducing LDL-C levels, over half of high-risk patients do not achieve guideline-recommended LDL-C goals. Thus, there is a significant gap between treatment guidelines and their implementation in daily clinical practice. The major causes are individual variability in the response to lipid-lowering therapies and variation in treatment adherence. Proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies combined with statins provide marked and consistent reduction in LDL-C levels; however, poor adherence due to the need for subcutaneous injections every 2 or 4 weeks and high cost are major obstacles to their use in real-world clinical settings. Inclisiran, a recently approved novel small interfering ribonucleic acid (siRNA) molecule that inhibits PCSK9 synthesis, provides robust and long-term reduction in LDL-C levels with a low inter-individual variability in the LDL-C-lowering response. Moreover, its administration by biannual injection is expected to greatly improve treatment adherence. Clinical trials of this drug lasting for up to 4 years showed acceptable safety profiles, and ongoing studies accumulate evidence of its longer-term safety. This narrative review summarizes the available evidence on the efficacy and safety of inclisiran and analyzes its potential to overcome the gap between guideline recommendations and real-world clinical practice in current LDL-C-lowering therapies, with a focus on reduced LDL-C level variability and improved treatment adherence.

Clearance of plasma PCSK9 via the asialoglycoprotein receptor mediated by heterobifunctional ligands

Proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates plasma low-density lipoprotein cholesterol (LDL-C) levels by promoting the degradation of hepatic LDL receptors (LDLRs). Current therapeutic approaches use antibodies that disrupt PCSK9 binding to LDLR to reduce circulating LDL-C concentrations or siRNA that reduces PCSK9 synthesis and thereby levels in circulation. Recent reports describe small molecules that, like therapeutic antibodies, interfere with PCSK9 binding to LDLR. We report an alternative approach to decrease circulating PCSK9 levels by accelerating PCSK9 clearance and degradation using heterobifunctional molecules that simultaneously bind to PCSK9 and the asialoglycoprotein receptor (ASGPR). Various formats, including bispecific antibodies, antibody-small molecule conjugates, and heterobifunctional small molecules, demonstrate binding in vitro and accelerated PCSK9 clearance in vivo. These molecules showcase a new approach to PCSK9 inhibition, targeted plasma protein degradation (TPPD), and demonstrate the feasibility of heterobifunctional small molecule ligands to accelerate the clearance and degradation of pathogenic proteins in circulation.

Mechanisms of unusual response to lipid-lowering therapy: PCSK9 inhibition

The efficacy of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition has broadened lipid-lowering therapy thus providing decreased risk in atherosclerotic cardiovascular disease. Unfortunately, the widespread use of PCSK9 inhibitors (PCSK9i), ie, monoclonal antibodies, has led to the findings of unusual responsiveness, ie, a phenomenon defined as an LDL-C reduction of <30% vs the average LDL-C reduction efficacy of 50-60%. This unusual responsiveness to PCSK9i is attributable to several factors, ie, lack of adherence, impaired absorption, poor distribution or early elimination as well as abnormal effects of PCSK9i in the presence of anti-antibodies or mutations in PCSK9 and LDLR. Unexpectedly increased lipoprotein (Lp)(a) also appear to contribute to the unusual responsiveness scenario. Identification of these responses and mechanisms underlying them are essential for effective management of LDL-C and cardiovascular risk. In this review, we describe plausible reasons underlying this phenomenon supported by findings of clinical trials. We also elaborate on the need for education and regular follow-up to improve adherence. Collectively, the review provides a summary of the past, present, and future of mechanisms and countermeasures revolving around unusual responses to PCSK9i therapy.

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.

Lipid-Modifying Therapies and Stroke Prevention

PURPOSE OF REVIEW

We reviewed lipid-modifying therapies and the risk of stroke and other cerebrovascular outcomes, with a focus on newer therapies.

RECENT FINDINGS

Statins and ezetimibe reduce ischemic stroke risk without increasing hemorrhagic stroke risk. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors similarly reduce ischemic stroke risk in statin-treated patients with atherosclerosis without increasing hemorrhagic stroke, even with very low achieved low-density lipoprotein cholesterol levels. Icosapent ethyl reduces the risk of total and first ischemic stroke in patients with established cardiovascular disease or diabetes mellitus. Clinical outcome trials are underway for newer lipid-modifying agents, including inclisiran, bempedoic acid, and pemafibrate. New biologic agents including evinacumab, pelacarsen, olpasiran, and SLN360 are also discussed. In addition to statins and ezetimibe, PCSK9 inhibitors and icosapent ethyl reduce the risk of ischemic stroke without increasing the risk of hemorrhagic stroke. These therapies dramatically expand options for reducing stroke in high-risk settings.

PCSK9 acts as a key regulator of Aβ clearance across the blood-brain barrier

Despite the neurodegenerative disorder Alzheimer's disease (AD) is the most common form of dementia in late adult life, there is currently no therapy available to prevent the onset or slow down the progression of AD. The progressive cognitive decline in AD correlates with a successive accumulation of cerebral amyloid-β (Aβ) due to impaired clearance mechanisms. A significant percentage is removed by low-density lipoprotein receptor-related protein 1 (LRP1)-mediated transport across the blood-brain barrier (BBB) into the periphery. Circulating proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to members of the low-density lipoprotein receptor protein family at the cell surface and targets them for lysosomal degradation, which reduces the number of functional receptors. However, the adverse impact of PCSK9 on LRP1-mediated brain Aβ clearance remains elusive. By using an established BBB model, we identified reduced LRP1-mediated brain-to-blood Aβ clearance due to PCSK9 across different endothelial monolayer in vitro. Consequently, the repetitive application of FDA-approved monoclonal anti-PCSK9 antibodies into 5xFAD mice decreased the cerebral Aβ burden across variants and aggregation state, which was not reproducible in brain endothelial-specific LRP1^-/- 5xFAD mice. The peripheral PCSK9 inhibition reduced Aβ pathology in prefrontal cortex and hippocampus-brain areas critically involved in memory processing-and prevented disease-related impairment in hippocampus-dependent memory formation. Our data suggest that peripheral inhibition of PCSK9 by already available therapeutic antibodies may be a novel and easily applicable potential AD treatment.

NAFLD fibrosis score is correlated with PCSK9 and improves outcome prediction of PCSK9 in patients with chest pain: a cohort study

Background

The risk of liver fibrosis in non-alcoholic fatty liver disease (NAFLD) can be easily evaluated by noninvasive scoring systems, of which the NAFLD fibrosis score (NFS) is the most commonly used. Proprotein convertase subtilisin/kexin type 9 (PCSK9), a new predictor of cardiovascular events, has been reported to be associated with cardiovascular outcomes and NAFLD. However, the relationship of NFS with PCSK9 and their prognostic abilities in cardiovascular risks are unknown.

Methods

A total of 2008 hospitalized subjects who had chest pain without lipid-lowering therapy were consecutively included. Baseline clinical data were collected, and the NFS was calculated. The circulating PCSK9 concentration was determined by enzyme immunoassay. The major adverse cardiovascular event (MACE) occurrences were recorded in the follow-up period. Associations of PCSK9 concentration with NFS were examined. All of the participants were categorized into three groups according to NFS levels and were further stratified by PCSK9 tertiles to evaluate the MACEs.

Results

158 (7.87%) MACEs were observed during a mean of 3.2 years of follow-up. NFS levels were independently related to higher PCSK9 levels according to multivariable linear regression analysis. Furthermore, elevated PCSK9 and NFS concentrations were respectively associated with increased MACE incidence in multivariable Cox regression models. When combining NFS status with PCSK9 tertiles as a stratifying factor, patients with intermediate-high NFS and high PCSK9 levels had higher risks of events than those with low NFS and low PCSK9 levels.

Conclusions

This study revealed for the first time that NFS is positively related to PCSK9 and that the combination of NFS and PCSK9 greatly increased the risk of MACEs in patients with chest pain, providing a potential link between NFS and PCSK9 for predicting cardiovascular events.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01610-w.

Efficacy and safety of inclisiran a newly approved FDA drug: a systematic review and pooled analysis of available clinical studies

Study objective

This systematic review and meta-analysis aimed to assess the efficacy and safety profile of treatment with inclisiran, a drug that has been recently approved by the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA).

Design

A systematic literature search was conducted in order to identify randomized controlled trials (RCTs) assessing the effect on lipoproteins and the safety profile of inclisiran.

Results

Data were pooled from 5 RCTs, which included 4226 subjects. Meta-analyses of data suggested that the multiple-dose regimens of inclisiran yielded a significant reduction in serum levels of proprotein convertase subtilisin/kexin type 9 (MD = -78.23%, 95%CI: -86.74, -69.71) and low-density lipoprotein cholesterol (MD = -45.48%, 95%CI: -50.36%, -40.61%) throughout the studies. Furthermore, treatment with inclisiran significantly affected total cholesterol (MD = -13.67%, 95%CI: -20.78%, -6.57%), high-density lipoprotein cholesterol (MD = 8.29%, 95%CI: 4.66%,11.93%), non-HDL cholesterol (MD = -39.45%, 95%CI: -43.6%, -35.31%), apolipoprotein B (MD = -34.58%, 95%CI: -38.78%, -30.78%) and lipoprotein(a) (MD = -20.9%, 95%CI: -25.8%, -15.99%). Multiple-dose regimens of inclisiran were associated with increased risk of injection-site reactions (any reaction: OR = 5.86, 95%CI: 3.44, 9.98; mild reactions: OR = 5.19, 95%CI: 1.68, 16.07; moderate reactions: OR = 13.37, 95%CI: 3.17, 56.46), and bronchitis (OR = 1.58, 95%CI: 1.10, 2.26), while the incidence of the pre-specified exploratory CV endpoint significantly decreased at 18 months (OR = 0.74, 95%CI: 0.58, 0.94).

Conclusion and relevance

Inclisiran has favourable effects on serum lipid levels and an acceptable safety profile. Further well-designed RCTs are needed to explore its longer-term safety.

Dyslipidemia in Chronic Kidney Disease: Contemporary Concepts and Future Therapeutic Perspectives

BACKGROUND

Chronic kidney disease (CKD) is an increasingly prevalent disease state met with great morbidity and mortality primarily resulting from the high incidence of adverse cardiovascular outcomes. Therapeutic strategies in this patient population aim at controlling modifiable cardiovascular risk factors, including dyslipidemia.

SUMMARY

In this review article, we first provide the latest pathophysiologic evidence regarding the altered dyslipidemia pattern in CKD, followed by its contemporary management according to the latest guidelines. Moreover, we present the current progress regarding the emerging therapeutic strategies. Key Messages: The presence of renal impairment leads to alterations in cholesterol structure, metabolism, and reverse transport paired with increased oxidative stress. Statins remain the cornerstone of dyslipidemia management in patients with kidney dysfunction who are at risk for cardiovascular events. However, their efficacy is debatable in end-stage renal disease under renal replacement therapy. Therefore, novel treatment approaches aiming at hypertriglyceridemia, proprotein convertase subtilisin/kexin type 9, and lipoprotein(a) are under rigorous investigation while the research of gut microbiome might provide additional mechanistic and therapeutic insight.

Design and rationale of the EVOCATION trial: A prospective, randomized, exploratory study comparing the effect of evolocumab on coronary microvascular function after percutaneous coronary intervention in patients with stable coronary artery disease

Percutaneous coronary intervention (PCI) is a standard treatment in patients with stable coronary artery disease (CAD); however, periprocedural myocardial infarction (PMI) remains a common complication of PCI. Aggressive lipid-lowering therapy with statin has shown to reduce the incidence of PMI by preventing coronary microvascular dysfunction. It is unclear whether evolocumab, a potent lipid-lowering agent, could diminish microvascular damage after PCI. The EVOCATION trial (jRCTs051180022) is a multicenter, randomized, open-label, active-controlled, parallel-group, exploratory, investigator-initiated clinical study to evaluate whether pretreatment with evolocumab could decrease the index of microvascular resistance (IMR) after PCI in patients with stable CAD. This study population consists of 100 patients with stable CAD who will undergo PCI and have high low-density lipoprotein cholesterol levels despite administration of maximum tolerated dose of statins for at least 2 weeks. Eligible patients are randomized in a 1:1 ratio to receive either evolocumab 140 mg every 2 weeks in addition to standard of care treatment or standard of care treatment only for 2-6 weeks before PCI. The primary endpoint is IMR after PCI. The EVOCATION trial will evaluate whether pretreatment with evolocumab reduces periprocedural microvascular damage in patients with stable CAD undergoing PCI.

Potential of Phage Display Antibody Technology for Cardiovascular Disease Immunotherapy

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

Achilles Tendon Thickness Assessed by X-ray Predicting a Pathogenic Mutation in Familial Hypercholesterolemia Gene

AIM

The 2017 Japan Atherosclerosis Society (JAS) familial hypercholesterolemia (FH) criteria adopt a cut-off value of ≥ 9 mm of Achilles tendon thickness (ATT) detected by X-ray as one of the three key items. This threshold was determined based on an old data evaluating the ATT of 36 non-FH individuals that was published in 1977. Although the specificity of these clinical criteria is extremely high due to a strict threshold, there are a significant number of patients with FH whose ATT ＜9 mm. We aimed to determine a cut-off value of ATT detected by X-ray to differentiate FH and non-FH based on genetic diagnosis.

METHODS

The individuals (male/female=486/501) with full assessments of genetic analyses for FH-genes (LDLR and PCSK9), serum lipids, and ATT detected by X-ray at the Kanazawa University Hospital and National Cerebral and Cardiovascular Center Research Institute were included in this study. Receiver operating characteristic (ROC) analyses were conducted to determine a better cut-off value of ATT that predicts the pathogenic mutation of FH.

RESULTS

The ROC analyses revealed that the best cut-off values of ATT are 7.6 mm for male and 7.0 mm for female, with the sensitivities/specificities of 0.83/0.83 for male and 0.86/0.85 for female, respectively. If the thresholds of ATT of 8.0/7.5 mm and 7.5/7.0 mm were applied to the diagnosis of male/female FH, the sensitivities/specificities predicting the pathogenic mutation of FH by the 2017 JAS FH clinical criteria would be 0.82/0.90 and 0.85/0.88, respectively.

CONCLUSIONS

These results suggest that the cut-off value of ATT detected by X-ray is obviously lower than 9.0 mm, which was adopted by the 2017 JAS FH clinical criteria.

Construction of point mutation rabbits using CRISPR/Cas9

To establish a rabbit model of proprotein convertase subtilisin/kexin type9 () point mutation with CRISPR/Cas9 gene editing technique. According to the PubMed gene protein data, the PCSK9 protein functional regions of human and rabbit were analyzed by Blast. The 386S (Ser) amino acid functional region of human gene was homologous to the 485S of rabbit gene. Three small guide RNAs and one single-stranded donor oligonucleotide were designed according to the 485S base substitution position and sequence analysis of rabbit gene. The synthetic small guide RNAs, Cas9 mRNA and single-stranded donor oligonucleotide were co-injected into the cytoplasm of rabbit fertilized eggs and the embryos were transferred into the pregnant rabbits. PCR, TA cloning and off-target analysis were performed on the F0 rabbits to identify whether the PCSK9 mutation was successful. Fifteen F0 rabbits were obtained. The sequencing results showed that one of them was PCSK9 point mutation homozygote and two of them were PCSK9 point mutation heterozygotes, and the mutation could be stably inherited. The rabbit model of PCSK9 point mutation was successfully constructed by CRISPR/Cas9 technique, which provides an animal model for exploring the molecular mechanism of impaired PCSK9 function and developing reliable and effective diagnosis and treatment measures.

Effect of PCSK9 on Vascular Smooth Muscle Cell Functions: A New Player in Atherosclerosis

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secretory serine protease that plays multiple biological functions in the regulation of physiological and pathological processes. PCSK9 inhibitors decrease the circulating LDL-cholesterol level with well-known preventive and therapeutic effects on atherosclerosis (AS), but increasing evidence shows that the direct impact of PCSK9 on the vascular wall also plays an important role in atherosclerotic progression. Compared with other vascular cells, a large proportion of PCSK9 is originated from vascular smooth muscle cells (VSMC). Therefore, defining the effect of VSMC-derived PCSK9 on response changes, such as phenotypic switch, apoptosis, autophagy, inflammation, foam cell formation, and calcification of VSMC, helps us better understand the "pleiotropic" effects of VSMC on the atherosclerotic process. In addition, our understanding of the mechanisms of PCSK9 controlling VSMC functions in vivo is far from enough. This review aims to holistically evaluate and analyze the current state of our knowledge regarding PCSK9 actions affecting on VSMC functions and its mechanism in atherosclerotic lesion development. A mechanistic understanding of PCSK9 effects on VSMC will further underpin the success of a new therapeutic strategy targeting AS.

High-sugar feeding and increasing cholesterol levels in infants

Hypercholesterolaemia is an important risk factor for cardiovascular disease. Both total and LDL cholesterol levels are three-fold higher at the end of the first year of life and about four-fold higher in adulthood compared with the neonatal period. In the USA, only 25% of infants are exclusively breastfed and simple carbohydrate-rich formulas are preferentially consumed. Spikes in fasting glucose and insulin have been reported in formula-fed infants and are associated with higher levels of proprotein convertase subtilisin/kexin type 9, suggesting a potential link between high simple sugar intake and consequent increase in LDL cholesterol in early childhood.

Pcsk9 is associated with severity of coronary artery lesions in male patients with premature myocardial infarction

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (Pcsk9) correlated with incidence and prognosis of coronary heart disease. However, it is unclear whether Pcsk9 contributed to coronary artery lesion severity in patients with premature myocardial infarction (PMI). The present study investigated associations between Pcsk9 and coronary artery lesion severity in PMI patients who underwent coronary angiography (CAG).

METHODS

This prospective cohort study included young men (age ≤ 45 years, n = 332) with acute MI who underwent CAG between January 2017 and July 2019. Serum Pcsk9 levels and clinical characteristics were evaluated. SYNTAX scores (SYNergy between percutaneous coronary intervention with [paclitaxel-eluting] TAXUS stent and cardiac surgery) were calculated to quantify coronary artery lesions.

RESULTS

Serum Pcsk9 levels were positively associated with SYNTAX scores (r = 0.173, P < 0.05). The diagnostic cutoff value of PSCK9 level was 122.9 ng/mL, yielding an area under the curve (AUC) of 0.63, sensitivity 81%, and specificity 40%. Serum Pcsk9, LDL-C, Apob, NT-proBnp, CK level, and diabetes history were independent predictors of high SYNTAX scores (P < 0.05). After stratifying by serum LDL-C level (cutoff = 2.6 mmol/L), medium-high Pcsk9 levels had increased risk of high SYNTAX scores in patients with high LDL-C (P < 0.05), and higher serum Pcsk9 levels had increased risk of major adverse cardiac events (MACE) after adjusting for confounding factors (P < 0.05).

CONCLUSION

Serum Pcsk9 levels correlates with severity of coronary artery lesion in PMI patients and may serve as a biomarker for severity of coronary artery stenosis in this patient population, which may contribute to risk stratification.

Clinical Diagnostic Criteria of Familial Hypercholesterolemia - A Comparison of the Japan Atherosclerosis Society and Dutch Lipid Clinic Network Criteria

BACKGROUND

This study is aimed to compare the efficacy of the 2017 Japan Atherosclerosis Society (JAS) familial hypercholesterolemia (FH) criteria, which focuses on only 3 essential clinical manifestations, with that of Dutch Lipid Clinic Network (DLCN) FH criteria, which adopts a scoring system of multiple elements.Methods and Results:A total of 680 Japanese dyslipidemic participants (51% men) were enrolled between 2006 and 2018, all of whom had full evaluations of low-density lipoprotein (LDL) cholesterol, Achilles tendon X-rays, family history records, and genetic analysis of FH-associated genes (LDLR,APOB, andPCSK9). Predictive values for the existence of FH mutations by both clinical criteria were evaluated. Overall, 173 FH patients were clinically diagnosed by using the 2017 JAS criteria and 100, 57, 156, and 367 subjects were also diagnosed as having definite, probable, possible, and unlikely FH by the DLCN FH criteria, respectively. The positive and negative likelihood ratio predicting the presence of FH mutations by using the 2017 JAS FH criteria were 19.8 and 0.143, respectively; whereas, using the DLCN criteria of definite, probable, and possible FH, the ratios were 29.2 and 0.489, 9.70 and 0.332, and 3.43 and 0.040, respectively.

CONCLUSIONS

Among Japanese patients, the JAS 2017 FH criteria is considered superior to diagnose FH mutation-positive patients and simultaneously rule out FH mutation-negative patients compared with the DLCN FH criteria.

Inducible degrader of LDLR: A potential novel therapeutic target and emerging treatment for hyperlipidemia

Statins are the most effective lipid-lowering drugs ever developed, and numerous patients with cardiovascular disease (CVD) have obtained remarkable benefits from statin therapy. However, issues with statin resistance and intolerance cannot be ignored in clinical practice. Additionally, adverse effects, such as an increased risk of new-onset diabetes and muscle symptoms, may limit the utilization of statins. Therefore, the development of new lipid-lowering agents is necessary to reduce CVD risk in patients who are unable to receive statin therapy. Among these new lipid-lowering strategies, inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) is an effective way to enhance clearance of LDL-C from the circulation by impeding the degradation of LDL receptor (LDLR) in hepatocytes. Interestingly, given that upregulation of LDLR is an effective method for lowering lipid levels, the question arises as to whether other LDLR-mediated genes could serve as potential therapeutic targets for CVD. As an E3-ubiquitin ligase, inducible degrader of LDLR (IDOL) can cause ubiquitination and degradation of LDLR in lysosome and is a novel regulator of LDLR expression similar to PCSK9. Although there are no approved drugs for targeting the IDOL-LDLR pathway, recent studies demonstrate that IDOL could serve as a potential therapeutic target for hyperlipidemia. Herein, we have summarized these novel studies to present the pathological role of IDOL in CVD, further assessing its pharmacological effects for lipid-lowering therapy.

Current Approach to the Diagnosis and Treatment of Heterozygote and Homozygous FH Children and Adolescents

Purpose of Review

To elucidate the current approach of care in pediatric patients with familial hypercholesterolemia (FH). We sought an answer to the question whether the advances and major changes in lipid management are relevant and apply to children and adolescents.

Recent Findings

Latest research findings clearly demonstrate that lowering cholesterol levels at a young age prevents vascular atherosclerotic changes and decreases cardiovascular events in adulthood and emphasizes the importance of early detection and intervention in the pediatric FH patients group.

Summary

FH is a common genetic disease caused by mutations in genes associated with the metabolism of low-density lipoproteins (LDL). The hallmark of FH is elevated LDL cholesterol (LDL-C) levels from birth and premature atherosclerotic cardiovascular disease (ASCVD). Often FH is either undiagnosed or diagnosed with a considerable delay, leading to vascular atherosclerotic changes and cardiovascular disease. Prompt identification of FH subjects is essential, to initiate early preventive measures. Safe and efficient pharmacological agents are approved for use in children and adolescents. Statins are the first line of therapy, in combination of ezetimibe. Unfortunately, these drugs do not warrant the achievement of therapeutic target, especially in HoFH patient. In the latter, lipoprotein apheresis (LA), which has been shown to be safe and effective, is strongly recommended. Finally, the new drugs still under study will allow a multimodal customized treatment. Lowering cholesterol levels at a young age hinders vascular atherosclerotic changes decreasing cardiovascular events in adulthood. Therefore, early detection, diagnosis, and intervention in FH patients are priority objectives.

Lipid Lowering Drugs: Present Status and Future Developments

Purpose of review

Based on the recent data of the DA VINCI study, it is clear that, besides utilization of statins, there is a need to increase non-statin lipid lowering approaches to reduce the cardiovascular burden in patients at highest risk.

Recent findings

For hypercholesterolemia, the small synthetic molecule bempedoic acid has the added benefit of selective liver activation, whereas inclisiran, a hepatic inhibitor of the PCSK9 synthesis, has comparable effects with PCSK9 monoclonal antibodies. For hypertriglyceridemia, cardiovascular benefit has been achieved by the use of icosapent ethyl, whereas results with pemafibrate, a selective agonist of PPAR-α, are eagerly awaited. In the era of RNA-based therapies, new options are offered to dramatically reduce levels of lipoprotein(a) (APO(a)L_RX) and of triglycerides (ANGPTL3L_RX and APOCIII-L_Rx).

Summary

Despite the demonstrated benefits of statins, a large number of patients still remain at significant risk because of inadequate LDL-C reduction or elevated blood triglyceride-rich lipoproteins or lipoprotein(a). The area of lipid modulating agents is still ripe with ideas and major novelties are to be awaited in the next few years.

Molecular genetic testing for autosomal dominant hypercholesterolemia in 29,449 Norwegian index patients and 14,230 relatives during the years 1993-2020

BACKGROUND AND AIMS

In this study, we present the status regarding molecular genetic testing for mutations in the genes encoding the low density lipoprotein receptor (LDLR), apolipoprotein B (APOB) and proprotein convertase subtilisin/kexin type 9 (PCSK9) as causes of autosomal dominant hypercholesterolemia (ADH) in Norway.

METHODS

We have extracted data from the laboratory information management system at Unit for Cardiac and Cardiovascular Genetics, Oslo University Hospital for the period 1993-2020. This laboratory is the sole laboratory performing molecular genetic testing for ADH in Norway.

RESULTS

A total of 29,449 unrelated hypercholesterolemic patients have been screened for mutations in the LDLR gene, in the APOB gene and in the PCSK9 gene. Of these, 2818 (9.6%) were heterozygotes and 11 were homozygotes or compound heterozygotes. Most of the 264 different mutations identified were found in the LDLR gene. Only two and three mutations were found in the APOB gene or in the PCSK9 gene, respectively. Several founder mutations were identified. After testing of 14,230 family members, a total of 8811 heterozygous patients have been identified. Of these, 94.0% had a mutation in the LDLR gene, 5.4% had a mutation in the APOB gene and 0.6% had a mutation in the PCSK9 gene.

CONCLUSIONS

A large proportion of Norwegian ADH patients have been provided with a molecular genetic diagnosis. Norway is probably only second to the Netherlands in this respect. A molecular genetic diagnosis may form the basis for starting proper preventive measures and for identifying affected family members by cascade genetic screening.

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.

Elevated levels of serum PCSK9 in male patients with symptomatic peripheral artery disease: The CAVASIC study

BACKGROUND AND AIMS

Peripheral artery disease (PAD) affects more than 200 million people worldwide. Increased low-density lipoprotein cholesterol (LDL-C)levels are a risk factor for PAD and the concentrations are influenced by proprotein convertase subtilisin/kexin type 9 (PCSK9). PCSK9 regulates the recycling of the LDL receptors to the cell membrane surface. Only a limited number of mostly small studies investigated the association between serum PCSK9 concentrations and PAD of different definition, which revealed contrasting results.

METHODS

Serum PCSK9, lipoprotein(a) [Lp(a)] and other lipoprotein concentrations were measured in male participants of the CAVASIC study, a case-control study of 248 patients with intermittent claudication and 251 age and diabetes-matched controls.

RESULTS

PAD patients had significantly higher PCSK9 concentrations when compared to controls (250 ± 77 vs. 222 ± 68 ng/mL, p < 0.001). Logistic regression analysis with adjustment for age revealed that an increase in PCSK9 concentrations of 100 ng/mL was associated with a 1.78-fold higher risk for PAD (95%CI 1.38-2.33, p = 1.43 × 10^-5). The association attenuated, but was still significant when adjusting additionally for age, Lp(a)-corrected LDL cholesterol, HDL cholesterol, high-sensitivity-CRP, statin treatment, hypertension, diabetes mellitus and smoking (OR = 1.49, 95%CI 1.03-2.18, p = 0.035). The strongest association was observed when both PCSK9 concentrations were above the median and Lp(a) concentrations were above 30 mg/dL (OR = 3.35, 95%CI 1.49-7.71, p = 0.0038).

CONCLUSIONS

Our findings suggest an association of higher PCSK9 concentrations with PAD, which was independent of other lipid parameters and classical cardiovascular risk factors.

Single-Strand DNA-Like Oligonucleotide Aptamer Against Proprotein Convertase Subtilisin/Kexin 9 Using CE-SELEX: PCSK9 Targeting Selection

BACKGROUND

Proprotein convertase subtilisin/kexin 9 (PCSK9) serves a key regulatory function in the metabolism of low-density lipoprotein (LDL)-cholesterol (LDL-C) through interaction with the LDL receptor (LDLR) followed by its destruction that results in the elevation of the plasma levels of LDL-C. The aims of the present study were to separate and select a number of single-stranded DNA (ssDNA) aptamers against PCSK9 from a library pool (n > 10¹²) followed by their characterization.

METHODS

The aptamers obtained from the DNA-PCSK9 complexes which presented the highest affinity against PCSK9 were separated and selected using capillary electrophoresis evolution of ligands by exponential enrichment (CE-SELEX). The selected aptamers were amplified and cloned into a T/A vector. The plasmids from the positive clones were extracted and sequenced. The Mfold web server was used to predict the secondary structure of the aptamers.

RESULTS

Following three rounds of CE-SELEX, the identified anti-PCSK9 ssDNA aptamers, namely aptamer 1 (AP-1) and aptamer 2 (AP-2), presented half maximal inhibitory concentrations of 325 and 327 nM, lowest dissociation constants of 294 and 323 nM, and most negative Gibbs free energy values of - 9.17 and - 8.28 kcal/mol, respectively.

CONCLUSION

The results indicated that the selected aptamers (AP-1 and AP-2) induced potent inhibitory effects against PCSK9. Further in vivo studies demand to find out AP-1 and AP-2 aptamers as suitable candidates, instead of antibodies, for using in therapeutic purposes in patients with hypercholesterolemia and cardiovascular disease.

In vitro selection generates RNA aptamer that antagonizes PCSK9-LDLR interaction and recovers cellular LDL uptake

Proprotein convertase subtilisin/kexin type 9 (PCSK9) induces low-density lipoprotein (LDL)-receptor (LDLR) degradation, increasing plasma LDL-cholesterol levels and causing hypercholesterolemia. Therefore, inhibition of PCSK9-LDLR interaction is an attractive therapeutic target for hypercholesterolemia treatment. In this study, we have identified a novel RNA aptamer that binds specifically to PCSK9 by in vitro selection, also known as systematic evolution of ligands by exponential enrichment (SELEX). The binding kinetics of the PCSK9-binding RNA aptamer was measured by biolayer interferometry assay, showing that the aptamer has higher affinity compared to PCSK9-LDLR interaction. Competitive inhibition assay using chemiluminescence detection revealed that the RNA aptamer inhibits PCSK9-LDLR interaction. In cellular LDL-uptake assays with HepG2 cells, the RNA aptamer recovered LDL uptake in the PCSK9-treated cells, demonstrating its anti-PCSK9 antagonistic activity. These results indicated that the PCSK9-binding RNA aptamer has the potential to be an affinity reagent for PCSK9 protein analysis and a therapeutic reagent for hypercholesterolemia treatment.

A reassessment of the Japanese clinical diagnostic criteria of familial hypercholesterolemia in a hospital-based cohort using comprehensive genetic analysis

Background

Clinical diagnostic criteria of familial hypercholesterolemia (FH) in Japan include LDL cholesterol ​≥ ​180 ​mg/dL, Achilles tendon thickness ​≥ ​9.0 ​mm, and family history. However, few data exist regarding its validation.

Design and Methods

A series of 680 participants, with a mean LDL cholesterol of 175 ​mg/dL were enrolled at Kanazawa University Hospital between 2006 and 2018. All had full assessments of, LDL cholesterol, Achilles tendon X-rays, family history records, and genetic analysis of FH-associated genes (LDLR, APOB, and PCSK9). The area under the curve (AUC) of receiver operating characteristic (ROC) curve analysis predicting the presence of FH mutations by each clinical marker were assessed.

Results

The optimal cutoff values predicting the presence of an FH-associated mutation were 181 ​mg/dL for LDL cholesterol and ≥7.0 ​mm for Achilles tendon thickness. AUCs predicting FH mutations were 0.827 for Achilles tendon thickness ≥9.0 ​mm, 0.889 for LDL cholesterol ≥180 ​mg/dL, and 0.906 for family history. If Achilles tendon thickness ≥7.0 ​mm was used as a clinical criterion, then 41 participants (6%) were newly diagnosed with FH and 86 (12%) were newly misclassified as FH.

Conclusions

Current clinical diagnostic criteria of FH were validated in this cohort. We recommend considering a tentative diagnosis of “potential FH” if the Achilles tendon thickness is ​≥ ​7.0 ​mm and <9.0 ​mm rather than dismissing a diagnosis of FH.

•

Clinical diagnostic criteria of FH in Japan were well validated.

•

The best cutoff value of ATT for predicting FH mutation was 7.0 ​mm.

•

Threshold of ATT ≥7.0 ​mm increased the sensitivity to diagnose FH.

Activation of estrogen receptor α (ERα) is required for Alisol B23-acetate to prevent post-menopausal atherosclerosis and reduced lipid accumulation

The risk of atherosclerosis (AS) ascends among post-menopausal women, while current hormone replacement therapy exerts several adverse effects. Alisol B 23-acetate (AB23A), a tetracyclic triterpenoid isolated from the rhizome of Alisma orientale, was reported to show multiple physiological activities, including regulating lipid metabolism. According to molecular docking analysis, it was predicted to bind with estrogen receptor α (ERα). In this study, we aimed to observe the effect of AB23A on preventing post-menopausal AS and explore whether the mechanism was mediated by ERα. In vitro, free fatty acid (FFA) was applied to induce the abnormal lipid metabolism of L02 cells. In vivo, the ApoE^-/- mice were ovariectomized to mimic the cessation of estrogen. The high-fat diet was also given to induce post-menopausal AS. We demonstrated AB23A attenuated the accumulation of total cholesterol and triglyceride induced by free fatty acids in hepatocytes. In high-fat diet-ovariectomy-treated ApoE^-/- mice, AB23A eliminated lipids in blood and liver. AB23A not only reduced the synthesis of proprotein convertase subtilisin/kexin type 9 (PCSK9) through sterol-regulatory element binding proteins (SREBPs) but also suppressed the secretion of PCSK9 through silent information regulator 1 (SIRT1). Notably, AB23A promoted the expression of ERα in vivo and in vitro. The both ERα inhibitor and ERα siRNA were also applied in confirming whether the hepatic protective effect of AB23A was mediated by ERα. We found that AB23A significantly promoted the expression of ERα. AB23A could inhibit the synthesis and secretion of PCSK9 through ERα, lower the accumulation of triglyceride and cholesterol, and prevent post-menopausal AS.

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.

Beneficial impact of epigallocatechingallate on LDL-C through PCSK9/LDLR pathway by blocking HNF1α and activating FoxO3a

BACKGROUND

Green tea drinking has been proven to lower lipid and exert cardiovascular protection, while the potential mechanism has not been fully determined. This study was to investigate whether the beneficial impact of epigallocatechingallate (EGCG), a type of catechin in green tea on lipids is associated with proprotein convertase subtilisin/kexin type 9 (PCSK9) pathways.

METHODS

We studied the effects and underlying molecular mechanism of EGCG or green tea on regulating cholesterol from human, animal and in vitro.

RESULTS

In the age- and gender-matched case control observation, we found that individuals with frequent tea consumption (n = 224) had the lower plasma PCSK9 and low density lipoprotein cholesterol (LDL-C) levels compared with ones without tea consumption (n = 224, p < 0.05). In the high fat diet (HFD) fed rats, EGCG administration significantly lowered circulating PCSK9 concentration and liver PCSK9 expression, along with up-regulated LDL receptor (LDLR) expression but decreased level of LDL-C. In hepatic cell study, similar results were obtained regarding the impact of EGCG on LDLR and PCSK9 expression. The assay transposase-accessible chromatic with high-throughput sequencing (ATAC-seq) and subsequent results suggested that two transcription factors, hepatocyte nuclear factor-1α (HNF-1α) and forkhead box class O (FoxO) 3a involved in inhibitory action of EGCG on PCSK9 expression.

CONCLUSIONS

The present study demonstrates that EGCG suppresses PCSK9 production by promoting nuclear FoxO3a, and reducing nuclear HNF1α, resulting in up-regulated LDLR expression and LDL uptake in hepatocytes. Thereby inhibiting liver and circulating PCSK9 levels, and ultimately lowering LDL-C levels.

Homozygous familial hypercholesterolemia in a young woman with dual gene mutations of low-density lipoprotein receptor and proprotein convertase subtilisin/kexin type 9

A 28-year-old woman with a rare combination of homozygous LDLR and heterozygous PCSK9 mutations had a phenotype consistent with homozygous familial hypercholesterolemia. She reported a clinical history of coronary and extracoronary atherosclerosis treated with 3 coronary stenting procedures, one coronary bypass, and aortic and mitral valve replacements. Because the patient refused lipoprotein apheresis, lipid-lowering therapy with statins, ezetimibe, and evolocumab was started. The desired low-density lipoprotein cholesterol target was not achieved. Dose-escalated lomitapide therapy (up to 30 mg/d) was added, enabling achievement of low-density lipoprotein cholesterol levels of 45 mg/dL during 24 months' follow-up. During this period, no cardiovascular events or clinical evidence of side effects occurred. In this case, lomitapide has been used in combination with maximum-tolerated statin therapy to successfully treat a patient with a rare combination of mutations in both LDLR and PCSK9 genes.

Are anti-inflammatory agents and nutraceuticals - novel inhibitors of PCSK9?

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a protease which increases the lysosomal degradation of low density lipoprotein receptor (LDLR) resulting in elevated serum LDL-cholesterol levels. Elevated LDL-cholesterol is the main risk factor for cardiovascular disease (CVD). Antibodies to PCSK9 decrease LDL-cholesterol. Recent studies have suggested a direct relationship between PCSK9 and inflammation and the potential inhibitory effects of anti-inflammatory agents against this enzyme. Nutraceuticals are natural compounds, which have numerous anti-inflammatory and lipid-lowering effects. In this review we focus on anti-inflammatory substances and nutraceuticals, which are beneficial in treatment of dyslipidemia. We also reviewed the recent findings concerning the role of PCSK9 as the main target for molecular mechanisms of these substances.

LDL-Cholesterol-Lowering Therapy

The causal relation between elevated levels of LDL-C and cardiovascular disease has been largely established by experimental and clinical studies. Thus, the reduction of LDL-C levels is a major target for the prevention of cardiovascular disease. In the last decades, statins have been used as the main therapeutic approach to lower plasma cholesterol levels; however, the presence of residual lipid-related cardiovascular risk despite maximal statin therapy raised the need to develop additional lipid-lowering drugs to be used in combination with or in alternative to statins in patients intolerant to the treatment. Several new drugs have been approved which have mechanisms of action different from statins or impact on different lipoprotein classes.

Apolipoprotein(a) phenotype determines the correlations of lipoprotein(a) and proprotein convertase subtilisin/kexin type 9 levels in patients with potential familial hypercholesterolemia

BACKGROUND AND AIMS

The aim of this study is to investigate the relation between lipoprotein(a) [Lp(a)] and proprotein convertase subtilisin/kexin type 9 (PCSK9) concentrations, and their complex, in patients with potential familial hypercholesterolemia (FH), depending on apo(a) phenotype.

METHODS

The study included 205 patients with total cholesterol (TC) > 7.5 mmol/L and/or low density lipoprotein cholesterol (LDL-C)>4.9 mmol/L, 32 (15%) patients suffered from ischemic heart disease (IHD), 64 were taking statins. The diagnosis of FH was estimated according to the Dutch Lipid Clinics Network criteria. Lipid parameters, apoB-containing lipoprotein subfractions, Lp(a), PCSK9, Lp(a)-PCSK9 complex levels and apo(a) phenotype were determined. Depending on the apo(a) phenotype, all patients were divided into 2 groups: with high molecular weight (HMW) (n = 145) and low molecular weight (LMW) (n = 60) apo(a) phenotype.

RESULTS

The groups were comparable by all major clinical characteristics and biochemical parameters. In the whole group, PCSK9 concentration correlated with age, statins intake, Lp(a), TC and TG levels. Correlation between Lp(a) and PCSK9 levels was found only in the LMW apo(a) phenotype group independently of statins intake (r = 0.46, p < 0.001). Associations between Lp(a)-PCSK9 complex and large subfractions of intermediate (r = 0.30) and low-density lipoproteins (r = 0.30, p < 0.05 for both) were observed, with more significance in group 2 (r = 0.59, p < 0.005 and r = 0.40, p < 0.05, respectively).

CONCLUSIONS

In patients with potential familial hypercholesterolemia, positive correlations between concentrations of Lp(a) and PCSK9, as well as of Lp(a)-PCSK9 plasma complex with large subfractions of intermediate and low-density lipoproteins (IDL-1 and LDL-C), were determined by the LMW apo(a) phenotype.

Plasma proprotein convertase subtilisin/kexin type 9 concentration and recurrent cardiovascular events in patients with familial hypercholesterolemia

AIMS

Familial hypercholesterolemia patients are characterized by early onset of coronary artery calcification and atherosclerosis, and high incidence of cardiovascular events. Plasma proprotein convertase subtilisin/kexin type 9 was reported to be a predictor for cardiovascular risk in the general population. However, its prognostic value for predicting recurrent cardiovascular events in familial hypercholesterolemia patients remains undetermined.

METHODS

A total of 249 patients with molecularly and/or clinically (Dutch Lipid Clinic Network score > 6) defined familial hypercholesterolemia who had experienced a first cardiovascular event were consecutively included and plasma proprotein convertase subtilisin/kexin type 9 concentrations were measured by enzyme-linked immunosorbent assay. Coronary artery calcification was measured using Agatston method and coronary severity was assessed by Gensini score, respectively. All patients received standard lipid-lowering therapy and were followed-up for recurrent cardiovascular events. Univariate and multivariate regression and Cox analyses was used to calculate hazard ratios with 95% confidence interval.

RESULTS

Circulating proprotein convertase subtilisin/kexin type 9 concentrations were positively associated with coronary artery calcification scores and Gensini score by both univariate and multivariate analyses. During a mean follow-up of 43 ± 19 months, 29 (11.51%) recurrent cardiovascular events occurred. Kaplan-Meier analysis showed that patients with the highest proprotein convertase subtilisin/kexin type 9 levels had the lowest event-free survival time. Multivariable Cox regression analysis revealed that proprotein convertase subtilisin/kexin type 9 was independently associated with recurrent cardiovascular events (hazard ratio: 1.45, 95% confidence interval: 1.11-1.88). The combination of proprotein convertase subtilisin/kexin type 9 to Cox prediction model led to an enhanced predictive value for recurrent cardiovascular events.

CONCLUSIONS

Increased level of proprotein convertase subtilisin/kexin type 9 was a significant risk factor of atherosclerosis and independently predicted future recurrent cardiovascular events in familial hypercholesterolemia patients receiving standard lipid-lowering treatment.

The patient journey with proprotein convertase subtilisin/kexin type 9 inhibitors in community practice

BACKGROUND

Trials have demonstrated that proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are effective as an adjunct to statin therapy, but access and cost issues have limited their use in community practice.

OBJECTIVE

The aim of the study was to better understand patients' experiences when trying to obtain, fill, and use PCSK9 inhibitor therapy in community practice.

METHODS

We conducted a patient survey to evaluate patient experiences with PCSK9 inhibitors including medication initiation, indication for treatment, insurance approval status, medication persistence, and reason for discontinuation. The survey was emailed to 4740 adults who used a patient access support program.

RESULTS

Overall, 1327 of 4740 adults completed the survey (28.0% response rate). Of those, 75.0% were aged >60 years, 52.8% were male, and 92.4% were White. At the time of PCSK9 inhibitor prescription, 70.2% were not on a statin (with 84.4% of those not on a statin reporting statin intolerance). Overall, 74.6% of patients found the drug approval process to be "somewhat" or "very" burdensome. Among n = 1216 patients who initiated treatment, 33.7% discontinued by the time of the survey, with 50.0% taking the drug for 1 to 6 months. Patient out-of-pocket costs were the leading reported reason for discontinuation.

CONCLUSIONS

Most PCSK9 inhibitor users in community practice were not on a statin, presumably because of statin intolerance. The drug approval process and costs continue to be strong reasons for lower initiation of PCSK9 agents, as well as higher discontinuation rates.

The association of the PCSK9 rs562556 polymorphism with serum lipids level: a meta-analysis

Background

Studies had investigated the associations between proprotein convertase subtilisin/kexin type 9 SNP rs562556 and serum lipids levels and response to statin treatment, however, the results remained inconclusive. We conducted this meta-analysis to elucidate the relationship of rs562556 and serum lipids levels.

Methods

All eligible studies met the inclusion criteria were retrieved from multiple databases. Relative data were extracted from each study. Review Manager (version 5.3.5) and STATA 12.0 software was used to perform this meta-analysis. Pooled standardized mean difference (SMD) with 95% CI was employed to evaluate the association of rs562556 with serum lipids levels.

Results

A total of 7 eligible articles involving 4742 subjects were included in the final meta-analysis. The results revealed that the G carriers had lower levels of total cholesterol (SMD: 0.14, 95% Cl: 0.06–0.23, P = 0.001) and LDL-C(SMD: 0.13, 95% Cl: -0.55-0.22,P = 0.002) than the non-carriers. The statistical results also illustrated that the G carriers had lower relative risk (SMD: 1.38, 95% Cl: 1.02–1.85, P = 0.003) than the non-carriers.

Conclusions

The results of the current meta-analysis for the first time indicated the relevance of rs562556 and lower serum cholesterol levels.

Electronic supplementary material

The online version of this article (10.1186/s12944-019-1036-1) contains supplementary material, which is available to authorized users.

Delayed postprandial TAG peak after intake of SFA compared with PUFA in subjects with and without familial hypercholesterolaemia: a randomised controlled trial

Postprandial hypertriacylglycerolaemia is associated with an increased risk of developing CVD. How fat quality influences postprandial lipid response is scarcely explored in subjects with familial hypercholesterolaemia (FH). The aim of this study was to investigate the postprandial response of TAG and lipid sub-classes after consumption of high-fat meals with different fat quality in subjects with FH compared with normolipidaemic controls. A randomised controlled double-blind cross-over study with two meals and two groups was performed. A total of thirteen hypercholesterolaemic subjects with FH who discontinued lipid-lowering treatment 4 weeks before and during the study, and fourteen normolipidaemic controls, were included. Subjects were aged 18-30 years and had a BMI of 18·5-30·0 kg/m2. Each meal consisted of a muffin containing 60 g (70 E%) of fat, either mainly SFA (40 E%) or PUFA (40 E%), eaten in a random order with a wash-out period of 3-5 weeks between the meals. Blood samples were collected at baseline (fasting) and 2, 4 and 6 h after intake of the meals. In both FH and control subjects, the level of TAG and the largest VLDL sub-classes peaked at 2 h after intake of PUFA and at 4 h after intake of SFA. No significant differences were found in TAG levels between meals or between groups (0·25≤P≤0·72). The distinct TAG peaks may reflect differences in the postprandial lipid metabolism after intake of fatty acids with different chain lengths and degrees of saturation. The clinical impact of these findings remains to be determined.

Dyslipidemia induced inflammatory status, platelet activation and endothelial dysfunction in rabbits: Protective role of 10-Dehydrogingerdione

10-Dehydrogingerdione is a novel cholesteryl ester transfer protein (CETP) inhibitor of natural origin. Some synthetic CETP inhibitors have recently been reported to suppress proprotein convertase subtilisin/kexin type 9 (PCSK9). Therefore, the present study aimed mainly to clarify the effect of 10-Dehydrogingerdione on cellular adhesion inflammatory molecules, platelet activation and endothelial dysfunction markers in addition to PCSK9 as compared to atorvastatin in dyslipidemic rabbits. Dyslipidemia was induced in 30 male rabbits, distributed in 3 equal groups through feeding dietary cholesterol (0.5% w/w) for 3 months. Two dyslipidemic groups were concurrently treated with either atorvastatin or 10-Dehydrogingerdione (10 mg/kg/ day, p.o) and dietary cholesterol. One additional group including 10 normal rabbits fed normal diet served as normal control (NC) group. Both 10-Dehydrogingerdione and atorvastatin significantly reduced serum CETP level and activity as well as PCSK9 and low density lipoprotein cholesterol (LDL-C) levels but increased high density lipoprotein cholesterol (HDL-C) levels as compared to dyslipidemic control (DC) rabbits (p <  0.001). Both treatments also induced a marked decrease in the interferon-gamma (IFN-γ), soluble CD40 ligand (sCD40L) and soluble P-selectin (sP-selectin) levels, inflammatory cell infiltration, as well as atherogenic and coronary risk indexes in addition to aortic atheromatous changes and intima/media ratio, respectively as compared to the DC group (p <  0.001). The reduction in these markers showed a significant correlation with PCSK9 suppression and CETP inhibitory effect. Interestingly, 10-Dehydrogingerdione exerted a greater ameliorative potential regarding these biomarkers than atorvastatin. Our findings suggest that 10-Dehydrogingerdione is a promising PCSK9 inhibitor with a significant protective value against many atherosclerotic risk factors.

Efficacy and safety of alirocumab in individuals with type 2 diabetes mellitus with or without mixed dyslipidaemia: Analysis of the ODYSSEY LONG TERM trial

BACKGROUND AND AIMS

Alirocumab, a monoclonal antibody to proprotein convertase subtilisin/kexin type 9, significantly reduces low-density lipoprotein cholesterol (LDL-C). We evaluated the efficacy and safety of alirocumab in individuals with type 2 diabetes mellitus (T2DM) with versus without mixed dyslipidaemia (MDL, defined as baseline LDL-C ≥70 mg/dL [1.8 mmol/L] and triglycerides ≥150 mg/dL [1.7 mmol/L]).

METHODS

Data from 812 individuals with T2DM, from the placebo-controlled, 78-week, Phase 3 ODYSSEY LONG TERM trial of alirocumab 150 mg every 2 weeks (Q2W), on a background of maximally tolerated statins ± other lipid-lowering therapies, were pooled according to MDL status. Efficacy endpoints included percentage change from baseline to Week 24 in calculated LDL-C and other lipids/lipoproteins.

RESULTS

In individuals with T2DM who received alirocumab 150 mg Q2W, mean LDL-C changes from baseline to Week 24 were -62.6% (vs. -6.0% with placebo) in those with MDL and -56.1% (vs. 5.6%) in those without MDL, with no significant between-group difference (p-interaction = 0.0842). Risk-based LDL-C goals (<70 [1.8 mmol/L] or <100 mg/dL [2.6 mmol/L]) were achieved by 69.1% and 72.4% of alirocumab-treated individuals with and without MDL, respectively. Mean reductions in non-high-density lipoprotein cholesterol (49.2% and 47.8%) and apolipoprotein B (50.2% and 49.1%) with alirocumab were also similar in those with and without MDL, respectively. Treatment-emergent adverse event rates were comparable between alirocumab-treated individuals with T2DM, with and without MDL.

CONCLUSIONS

Reductions in LDL-C and other lipids with alirocumab, as well as safety and tolerability, were comparable between individuals with T2DM and with versus without MDL.

Role of PCSK9 in lipid metabolism and atherosclerosis

Elevated plasma low-density lipoprotein cholesterol (LDL-C) is an important risk factor for cardiovascular diseases. Statins are the most widely used therapy for patients with hyperlipidemia. However, a significant residual cardiovascular risk remains in some patients even after maximally tolerated statin therapy. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a new pharmacologically therapeutic target for decreasing LDL-C. PCSK9 reduces LDL intake from circulation by enhancing LDLR degradation and preventing LDLR recirculation to the cell surface. Moreover, PCSK9 inhibitors have been approved for patients with either familial hypercholesterolemia or atherosclerotic cardiovascular disease, who require additional reduction of LDL-C. In addition, PCSK9 inhibition combined with statins has been used as a new approach to help reduce LDL-C levels in patients with either statin intolerance or unattainable LDL goal. This review will discuss the emerging anti-PCSK9 therapies in the regulation of cholesterol metabolism and atherosclerosis.

Remnant-like particles and coronary artery disease in familial hypercholesterolemia

BACKGROUND

Although remnant-like particle cholesterol (RLP-C) has been associated with coronary artery disease (CAD) in the general population, few data exist regarding this issue in patients with familial hypercholesterolemia (FH). The aim of our study was to investigate the association between RLP-C and the presence of CAD in patients with FH.

METHODS

We examined 282 patients with FH (144 males, mean age, 41 ± 17 years) whose RLP-C levels were measured. We assessed the baseline characteristics, including lipid levels, other conventional risk factors for cardiovascular events, the presence of CAD, and the serum RLP-C levels.

RESULTS

Serum RLP-C levels significantly correlated with serum triglyceride (TG) levels (Pearson's r = 0.631, p < 0.001). We observed that a larger proportion of individuals in the higher tertiles of serum RLP-C had a larger number of diseased coronary arteries (p < 0.001 for the trend of multi-vessel disease). Logistic regression analysis, after adjusting for age, sex, hypertension, diabetes, smoking, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and lipoprotein (a) [Lp(a)], revealed that RLP-C was significantly associated with CAD [odds ratio (OR): 1.08, 95% confidence interval (CI): 1.00-1.16, p = 0.046]; however, adding serum TG levels into the logistic regression model nullified this association (OR: 1.07, 95% CI: 0.98-1.17, p = 0.141), whereas Lp(a) was independently associated with CAD (OR: 1.02, 95% CI: 1.00-1.03, p = 0.015).

CONCLUSIONS

Serum RLP-C levels were significantly associated with the presence and severity of CAD in patients with FH. However, the clinical usefulness of measuring RLP-C levels beyond that of measuring TG levels should be further assessed.

Association between lipoprotein (a) and proprotein convertase substilisin/kexin type 9 in patients with heterozygous familial hypercholesterolemia: A case-control study

BACKGROUND

Recent data have suggested an important role of lipoprotein (a) [Lp(a)] and proprotein convertase substilisin/kexin type 9 (PCSK9) in the development of atherosclerotic cardiovascular disease (ASCVD) in both general population and family hypercholesterolemia (FH), while the relation of Lp(a) to PCSK9 has not been examined.

OBJECTIVE

The aim of the present study was to investigate the association between plasma PCSK9 and Lp(a)in patients with heterozygous FH (HeFH).

METHODS

Two hundred and fifty-five molecularly confirmed patients with HeFH were compared to 255 age- and gender-matched non-FH controls. Plasma PCSK9 and Lp(a) concentrations were measured using ELISA and immunoturbidimetric method respectively, and finally their association was assessed.

RESULTS

Both plasma PCSK9 and Lp(a) levels were significantly higher in patients with HeFH compared to control group (p<0.001). Besides, the Lp(a) concentration and percentage of Lp(a)≥300mg/L were increased by PCSK9 tertiles in HeFH group (both p<0.05) while not in control group. In partial correlation analysis, Lp(a) was associated with PCSK9 (r=0.254, p<0.001) in HeFH group but not in control, which were further confirmed by multivariable linear regression analysis. Furthermore, significant associations between Lp(a) and PCSK9 were also found in subgroups of HeFH group irrespective of definite or probable FH, with and without coronary artery disease (CAD), and with statin or not.

CONCLUSIONS

Plasma Lp(a) level was associated with PCSK9 in patients with HeFH alone, suggesting that much about the interaction of PCSK9 with Lp(a) in FH need further explorations.

Circulating PCSK9 levels and 2-hPG are positively correlated in metabolic diseases in a Chinese Han population

Background

Proprotein convertase subtilisin/kexin type 9 (PCSK9), which plays a crucial role in lipoprotein metabolism, has been also regarded as an important marker for atherosclerosis. Available evidence indicated that 2-h postchallenge plasma glucose (2-hPG) could be another biomarker for atherosclerosis. However, currently the association between circulating PCSK9 and 2-hPG remains unclear. Here, we explored this potential link in a Chinese Han population.

Methods

Totally, 600 Chinese Han subjects from Nanjing district, China, were enrolled for the 75-g oral glucose tolerance test (OGTT), and they included normal glucose tolerance (NGT, n = 200), impaired glucose regulation (IGR, n = 200), and type 2 diabetes (T2DM, n = 200). Anthropometric and biochemical determinations such as serum lipid measurements were made. A sandwich ELISA assay was performed to measure serum PCSK9 levels in all subjects.

Results

Serum PCSK9 concentrations were higher in IGR group (77.63 ± 28.14 ng/ml) and T2DM group (90.62 ± 39.96 ng/ml) than in NGT group (65.33 ± 32.68 ng/ml), and it was significantly higher in T2DM group than in IGR group (p < 0.01). Serum PCSK9 levels positively correlated with 2-hPG and LDL-C in all subgroups, but presented a positive correlation with fasting blood glucose (FBG) only in T2DM group. Using multiple regression model analysis, we also found that PCSK9 levels closely correlated with 2-hPG in all tested groups. According to multinomial logistic regression analysis, PCSK9 levels positively correlated with T2DM (OR = 1.017[1.010–1.025], p < 0.001) even after adjustment for lipid levels. Moreover, in subjects with normal FBG level, 2-hPG gradually and significantly increased across PCSK9 tertiles (6.68 ± 2.01, 7.48 ± 2.10 and 8.27 ± 2.41 mmol/L, respectively, p < 0.01); however, in subjects with normal 2-hPG levels, no such difference was observed.

Conclusions

PCSK9 levels increase as glucose metabolism deteriorated. Serum PCSK9 levels positively correlated with 2-hPG in patients with metabolic diseases.