Protein Convertase Subtilisin/kexin Type 9 Research Articles

Primary and secondary prevention of stroke and cardiovascular events using evolocumab and alirocumab: Meta-analysis of randomized controlled trials.

Although the clinical role of protein convertase subtilisin kexin type 9 (PCSK9) inhibitors for cholesterol management is increasing, the post-marketing period of use is short compared to other lipid-lowering drugs, so there is still insufficient evidence for their efficacy and safety. In this meta-analysis, we evaluated preventive effects of stroke and cardiovascular (CV) events using evolocumab and alirocumab. We assessed the relative risk of stroke and CV events after alirocumab or evolocumab treatment in individuals with or without clinical CV diseases compared with that in controls. In addition, we evaluated the relative risk of hemorrhagic stroke. A total of 25 articles were included (median of study duration = 52 weeks). The risk of stroke was significantly decreased after treatment with alirocumab or evolocumab (primary prevention in patients without CV diseases: RR = 0.733; 95% CI, 0.618-0.870; secondary prevention in patients with CV diseases: RR = 0.703; 95% CI, 0.562-0.880). The risk of CV events also significantly decreased in patients treated with alirocumab or evolocumab (primary prevention: RR = 0.818; 95% CI, 0.777-0.861; secondary prevention: RR = 0.725; 95% CI, 0.578-0.910). The relative risk of hemorrhagic stroke was not significantly different between PCSK9 inhibitor-treated patients and controls (RR=1.041; 95% CI, 0.690-1.573). Our findings indicate that evolocumab and alirocumab are significantly effective without increasing the risk of hemorrhagic stroke. Based on this, the PCSK9 inhibitors can be highly recommended for cholesterol management.

E-cigarette exposure causes early pro-atherogenic changes in an inducible murine model of atherosclerosis.

Introduction: Evidence suggests that e-cigarette use (vaping) increases cardiovascular disease risk, but decades are needed before people who vape would develop pathology. Thus, murine models of atherosclerosis can be utilized as tools to understand disease susceptibility, risk and pathogenesis. Moreover, there is a poor understanding of how risk factors for atherosclerosis (i.e., hyperlipidemia, high-fat diet) intersect with vaping to promote disease risk. Herein, we evaluated whether there was early evidence of atherosclerosis in an inducible hyperlipidemic mouse exposed to aerosol from commercial pod-style devices and e-liquid. Methods: Mice were injected with adeno-associated virus containing the human protein convertase subtilisin/kexin type 9 (PCSK9) variant to promote hyperlipidemia. These mice were fed a high-fat diet and exposed to room air or aerosol derived from JUUL pods containing polyethylene glycol/vegetable glycerin (PG/VG) or 5% nicotine with mango flavoring for 4weeks; this timepoint was utilized to assess markers of atherosclerosis that may occur prior to the development of atherosclerotic plaques. Results: These data show that various parameters including weight, circulating lipoprotein/glucose levels, and splenic immune cells were significantly affected by exposure to PG/VG and/or nicotine-containing aerosols. Discussion: Not only can this mouse model be utilized for chronic vaping studies to assess the vascular pathology but these data support that vaping is not risk-free and may increase CVD outcomes later in life.

Established and Emerging Lipid-Lowering Drugs for Primary and Secondary Cardiovascular Prevention.

Despite treatment with statins, patients with elevated low-density lipoprotein cholesterol (LDL-C) and triglycerides remain at increased risk for adverse cardiovascular events. Consequently, novel pharmaceutical drugs have been developed to control and modify the composition of blood lipids to ultimately prevent fatal cardiovascular events in patients with dyslipidaemia. This article reviews established and emerging lipid-lowering drugs regarding their mechanism of action, development stage, ongoing clinical trials, side effects, effect on blood lipids and reduction in cardiovascular morbidity and mortality. We conducted a keyword search to identify studies on established and emerging lipid modifying drugs. Results were summarized in a narrative overview. Established pharmaceutical treatment options include the Niemann-Pick-C1 like-1 protein (NPC1L1) inhibitor ezetimibe, the protein convertase subtilisin-kexin type 9 (PCSK9) inhibitors alirocumab and evolocumab, fibrates as peroxisome proliferator receptor alpha (PPAR-α) activators, and the omega-3 fatty acid icosapent ethyl. Statins are recommended as the first-line therapy for primary and secondary cardiovascular prevention in patients with hypercholesterinaemia and hypertriglyceridemia. For secondary prevention in hypercholesterinaemia, second-line options such as statin add-on or statin-intolerant treatments are ezetimibe, alirocumab and evolocumab. For secondary prevention in hypertriglyceridemia, second-line options such as statin add-on or statin-intolerant treatments are icosapent ethyl and fenofibrate. Robust data for these add-on therapeutics in primary cardiovascular prevention remains scarce. Recent biotechnological advances have led to the development of innovative small molecules (bempedoic acid, lomitapide, pemafibrate, docosapentaenoic and eicosapentaenoic acid), antibodies (evinacumab), antisense oligonucleotides (mipomersen, volanesorsen, pelcarsen, olezarsen), small interfering RNA (inclisiran, olpasiran), and gene therapies for patients with dyslipidemia. These molecules specifically target new cellular pathways, such as the adenosine triphosphate-citrate lyase (bempedoic acid), PCSK9 (inclisiran), angiopoietin-like 3 (ANGPTL3: evinacumab), microsomal triglyceride transfer protein (MTP: lomitapide), apolipoprotein B-100 (ApoB-100: mipomersen), apolipoprotein C-III (ApoC-III: volanesorsen, olezarsen), and lipoprotein (a) (Lp(a): pelcarsen, olpasiran). The authors are hopeful that the development of new treatment modalities alongside new therapeutic targets will further reduce patients' risk of adverse cardiovascular events. Apart from statins, data on new drugs' use in primary cardiovascular prevention remain scarce. For their swift adoption into clinical routine, these treatments must demonstrate safety and efficacy as well as cost-effectiveness in randomized cardiovascular outcome trials.

Treatment with PCSK9 Inhibitor Evolocumab Improves Vascular Oxidative Stress and Arterial Stiffness in Hypercholesterolemic Patients with High Cardiovascular Risk.

Atherosclerosis and atherosclerotic-related cardiovascular diseases (ASCVD) are characterized by high serum levels of low-density lipoprotein cholesterol (LDL-C) that can promote the generation of reactive oxygen species (ROS). To answer the need for better LDL-C control in individuals at high and very high risk for CVD, a new injectable innovative family of lipid-lowering (LL) monoclonal antibodies against the protein convertase subtilisin/kexin type 9 (PCSK9) has been approved. However, the effect of these drugs on vascular function, such as ROS generation and arterial stiffness, has not already been extensively described. In this report, we present data from 18 males with high to very high CV risk undergoing LL treatment (LLT) with either statin and ezetimibe or ezetimibe monotherapy, who experienced, after a 2-month treatment with Evolocumab, a significant improvement in blood pressure (BP)-adjusted carotid-femoral pulse wave velocity (cfPWV) (p-value = 0.0005 in the whole cohort, p-value = 0.0046 in the sub-cohort undergoing background LLT with statin and ezetimibe, p-value = 0.015 in the sub-cohort undergoing background LLT with ezetimibe monotherapy), which was significantly associated with a decrease in freshly isolated leukocytes (PBMCS)-derived H2O2 production (p-value = 0.004, p-value = 0.02 and p-value = 0.05, respectively, in the whole cohort, in the statin + ezetimibe sub-cohort, and the ezetimibe sub-cohort). Our observations support the role of systemic oxidative stress in atherosclerosis and give a further rationale for using Evolocumab also for its effect in vascular disorders linked to oxidative processes.

Functional Characterization of p.(Arg160Gln) PCSK9 Variant Accidentally Found in a Hypercholesterolemic Subject

Familial hypercholesterolaemia (FH) is an autosomal dominant dyslipidaemia, characterised by elevated LDL cholesterol (LDL-C) levels in the blood. Three main genes are involved in FH diagnosis: LDL receptor (LDLr), Apolipoprotein B (APOB) and Protein convertase subtilisin/kexin type 9 (PCSK9) with genetic mutations that led to reduced plasma LDL-C clearance. To date, several PCSK9 gain-of-function (GOF) variants causing FH have been described based on their increased ability to degrade LDLr. On the other hand, mutations that reduce the activity of PCSK9 on LDLr degradation have been described as loss-of-function (LOF) variants. It is therefore important to functionally characterise PCSK9 variants in order to support the genetic diagnosis of FH. The aim of this work is to functionally characterise the p.(Arg160Gln) PCSK9 variant found in a subject suspected to have FH. Different techniques have been combined to determine efficiency of the autocatalytic cleavage, protein expression, effect of the variant on LDLr activity and affinity of the PCSK9 variant for the LDLr. Expression and processing of the p.(Arg160Gln) variant had a result similar to that of WT PCSK9. The effect of p.(Arg160Gln) PCSK9 on LDLr activity is lower than WT PCSK9, with higher values of LDL internalisation (13%) and p.(Arg160Gln) PCSK9 affinity for the LDLr is lower than WT, EC50 8.6 ± 0.8 and 25.9 ± 0.7, respectively. The p.(Arg160Gln) PCSK9 variant is a LOF PCSK9 whose loss of activity is caused by a displacement of the PCSK9 P' helix, which reduces the stability of the LDLr-PCSK9 complex.

An Updated Meta-Analysis for Safety Evaluation of Alirocumab and Evolocumab as PCSK9 Inhibitors.

Alirocumab and evolocumab, as protein convertase subtilisin kexin type 9 (PCSK9) inhibitors, have been reported to reduce cardiovascular risk. This meta-analysis is aimed at updating the safety data of PCSK9 inhibitors. We assessed the relative risk for all treatment-related adverse events, serious adverse events, diabetes-related adverse events, and neurocognitive and neurologic adverse events with PCSK9 inhibitors compared to controls (placebo or ezetimibe). In addition, we conducted a meta-analysis to quantitatively integrate and estimate the adverse event rates in long-term studies. There were no significant differences between PCSK9 inhibitors and controls in the relative risk analysis. In a subgroup analysis of each PCSK9 inhibitor, alirocumab treatment significantly reduced the risk of serious adverse events compared to control treatment (risk ratio (RR) = 0.937; 95% confidence interval (CI), 0.896-0.980), but no significant difference was observed with evolocumab treatment (RR = 1.003; 95% CI, 0.963-1.054). Moreover, alirocumab treatment afforded a significant reduction in the risk of diabetes-related adverse events compared to control treatment (RR = 0.9137; 95% CI, 0.845-0.987). The overall incidence (event rate) of long-term adverse events was 75.1% (95% CI, 71.2%-78.7%), and the incidence of serious long-term event rate was 16.2% (95% CI, 11.6%-22.3%). We suggest that alirocumab and evolocumab are generally safe and well tolerated and that their addition to background lipid-lowering therapy is not associated with an increased risk of adverse events or toxicity.

Smoking and diabetes attenuate beneficial effects of PSCK9 inhibitors on arterial wall properties in patients with very high lipoprotein (a) levels

Background and aimsElevated lipoprotein (a) (Lp(a)) and low-density lipoprotein cholesterol levels (LDL-C) are significant residual risk factors for cardiovascular events. Treatment with protein convertase subtilisin kexin type 9 (PCSK9) inhibitors reduces the levels of both. Less is known about effects of PCSK9 inhibitors on functional and morphological properties of the arterial wall. The aim of the present study was to determine whether other factors besides decreased LDL-C and Lp(a) are associated with functional (flow-mediated dilation [FMD]) and morphological (carotid intima-media thickness [c-IMT], pulse-wave velocity [PWV]) changes of the arterial wall properties in patients with coronary artery disease (CAD) treated with alirocumab and evolocumab. MethodsOne hundred patients with CAD after myocardial infarction before 55 years and with high Lp(a) were randomised to lipid-lowering therapies without PCSK9 inhibitors (control; N = 31), or with alirocumab 150 mg SC (N = 35) or evolocumab 140 mg SC (N = 34), every 2 weeks. All patients underwent blood sampling for biochemical analyses and ultrasound measurements for FMD, c-IMT and PWV. ResultsThere were no significant changes in FMD for the control (10.7% ± 6.6%–11.1% ± 4.4%, p = 0.716) and alirocumab (10.7% ± 5.9%–11.2% ± 5.3%, p = 0.547) groups, while evolocumab promoted significant increase (11.2% ± 6.8%–14.1% ± 6.6%, p < 0.0001). Only in non-smokers and non-diabetics significant improvements in FMD (p < 0.0001) after treatment with PCSK9 inhibitors were observed. ConclusionThese data show that for patients with CAD and high Lp(a) levels, beneficial effects of PCSK9 inhibitors on the arterial wall properties can be attenuated by specific risk factors, such as smoking and diabetes.

Association of PCSK9 levels and genetic polymorphisms with stroke recurrence and functional outcome after acute ischemic stroke.

BackgroundProtein convertase subtilisin/kexin type 9 (PCSK9) is a hepatic protein that participated in the lipid homeostasis. Its high levels and polymorphisms are associated with high low-density lipoprotein cholesterol, increasing the vascular risk potentially. However, the association between PCSK9 levels, genetic polymorphisms, and ischemic stroke remains unclear. We aimed to study the relationship between PCSK9 levels, genetic polymorphisms, and stroke outcomes in patients with ischemic stroke.MethodsA total of 9,782 acute ischemic stroke patients registered in the China National Stroke Registry-III were included in this prospective study. Circulating PCSK9 concentrations and 11 key single-nucleotide polymorphisms (SNPs) were examined. The clinical outcomes included stroke recurrence, death, and poor functional outcome at 12 months.ResultsThe median PCSK9 level was 361.28 ng/mL. After adjusting for confounders, patients in the highest quartile of circulating PCSK9 had a relatively lower risk of 12-month stroke recurrence (HR 0.80, 95% CI: 0.67–0.96). No significant relationship between PCSK9 level and death or poor functional outcome was found. No significant relationship between SNPs and stroke outcomes at 12 months was found.ConclusionsThe high level of PCSK9 was associated with decreased stroke recurrence at 12 months in ischemic stroke patients. There was no significant association between PCSK9 polymorphisms and acute ischemic stroke based on a Chinese registry.

Safety and efficacy of inclisiran in South African patients at high cardiovascular risk: A subanalysis of the ORION phase III clinical trials

Background. Inclisiran significantly reduced low-density lipoprotein cholesterol (LDL-C) in individuals with heterozygous familial hypercholesterolaemia, established atherosclerotic cardiovascular disease (ASCVD) or ASCVD risk equivalents (type 2 diabetes, familial hypercholesterolaemia or a 10-year risk of a cardiovascular event ≥20%) in the ORION phase III clinical trials. Infrequent dosing at days 1, 90, 270 and 450 resulted in a mean LDL-C reduction of ~50%. A total of 298 participants from South Africa (SA) were enrolled. Local data are needed to support the use of inclisiran in the SA population, potentially addressing an unmet need for additional LDL-C-lowering therapies. Objectives. To analyse the ORION phase III trial data to assess the efficacy and safety of inclisiran in SA participants. Methods. ORION-9, 10 and 11 were randomised, double-blind, phase III trials. Participants were receiving maximally tolerated statins with or without other lipid-lowering therapies (excluding protein convertase subtilisin/kexin type 9 (PCSK9) inhibitors). Participants were randomised 1:1 to inclisiran sodium 300 mg/284 mg (free acid) or placebo administered at days 1, 90, 270 and 450. The co-primary endpoints were the LDL-C percentage change from baseline to day 510 and the time-averaged percentage change in LDL-C from baseline after day 90 up to day 540. Key secondary endpoints included the absolute change in LDL-C from baseline to day 510, the time-averaged absolute change from baseline after day 90 up to day 540, and changes in other lipids and lipoproteins. Results. The mean age of the participants was 58.6 years (56% male). The mean LDL-C level at baseline was 3.6 mmol/L. At day 510, inclisiran reduced LDL-C levels by 54.2% compared with placebo (95% confidence interval (CI) –61.3 - –47.2; p&lt;0.0001). The corresponding time-averaged reduction in LDL-C was 52.8% (95% CI –57.9 - –47.8; p&lt;0.0001). Treatment-emergent adverse events at the injection site were more common with inclisiran compared with placebo (10.1% v. 0.7%); however, all were mild or moderate in nature and none were persistent. Conclusion. Inclisiran, given in addition to maximally tolerated standard lipid-lowering therapy, is effective and safe and results in robust reductions in LDL-C in SA patients at high cardiovascular risk.

A Comprehensive Review of PCSK9 Inhibitors.

Cardiovascular disease (CVD) is the leading cause of death in the United States and worldwide. A major risk factor for this condition is increased serum low-density lipoprotein cholesterol (LDL-C) levels for which statins have been successful in reducing serum LDL-C to healthy concentrations. However, patients who are statin intolerant or those who do not achieve their treatment goals while on high-intensity statin therapy, such as those with familial hypercholesterolemia, remain at risk. With the discovery of PCSK9 inhibitors, the ability to provide more aggressive treatment for patients with homozygous and heterozygous familial hypercholesterolemia has increased. Ezetimibe reduces LDL-C by 15%-20% when combined with statin.2,3 Protein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have been found to achieve profound reductions in LDL-C (54%-74%) when added to statins. They have shown dramatic effects at lowering major adverse cardiovascular events (MACE) in high-risk patients4 with LDL-C levels ≥70 mg/dL and can be used in populations that are statin intolerant or not at goal levels with maximally tolerated statin therapy. PCSK9 inhibitors also produce minimal side effects. Myopathy, a common side effect for patients on statins, has been rare in patients on PCSK9 inhibitors. Randomized trials have shown that reduction in LDL-C has translated to clinical benefits even in patients who have not achieved their LDL-C target.

Protein convertase subtilisin/Kexin type 9 inhibits hepatocellular carcinoma growth by interacting with GSTP1 and suppressing the JNK signaling pathway.

Objective:Protein convertase subtilisin/Kexin type 9 (PCSK9) has been found to be closely associated with the occurrence and development of numerous tumors. However, the precise role of PCSK9 and its relationship to the development of hepatocellular carcinoma (HCC) remain largely unknown. This study aimed to clarify these issues.Methods:The expression levels of PCSK9 in HCC tissues and HCC cell lines were determined by the quantitative reverse transcription polymerase chain reaction, Western blot, and immunohistochemical analyses, and the effects of PCSK9 expression on HCC cell biological traits were investigated by overexpressing and downregulating PCSK9 expression in vivo and in vitro. Additionally, the mechanism by which PCSK9 mediated dissociation of glutathione S-transferase Pi 1 (GSTP1) dimers and phosphorylation of the Jun N-terminal kinase (JNK) pathway components were investigated.Results:PCSK9 expression levels were significantly lower in HCC tissues than in adjacent non-tumor samples. In vivo and in vitro experiments suggested that PCSK9 inhibited HCC cell proliferation and metastasis. Further analysis showed that PCSK9 interacted with GSTP1 and promoted GSTP1 dimer dissociation and JNK signaling pathway inactivation in HCC cells. Moreover, the relationships between PCSK9 protein expressions and clinical outcomes were investigated. The PCSK9-lo group displayed a significantly shorter overall survival (OS; median OS: 64.2 months vs. 83.2 months; log-rank statistic: 4.237; P = 0.04) and recurrence-free survival (RFS; median RFS: 26.5 months vs. 46.6 months; log-rank statistic: 10.498; P = 0.001) time than the PCSK9-hi group.Conclusions:PCSK9 inhibited HCC cell proliferation, cell cycle progression, and apoptosis by interacting with GSTP1 and suppressing JNK signaling, suggesting that PCSK9 might act as a tumor suppressor and be a therapeutic target in HCC patients.

Genetics, Screening, and Treatment of Familial Hypercholesterolemia: Experience Gained From the Implementation of the Vietnam Familial Hypercholesterolemia Registry.

Familial hypercholesterolemia (FH) is underdiagnosed and undertreated in a majority of the low- and middle-income countries. FH registries could prove useful in bridging the knowledge gaps, supporting genetic and clinical research, and improving health-care planning and patient care. Here, we report the first usage experience of the Vietnam FH (VINAFH) Registry. The VINAFH Registry was established in 2016 as a long-term database for prospective cohorts. FH patients were detected based on the opportunistic and cascade screening. Diagnosis of FH was assessed using the Dutch Lipid Clinic Network criteria, plasma levels of low-density lipoprotein (LDL) cholesterol, and genetic testing. To date, a total of 130 patients with FH have been registered, with 48 index cases and 82 relatives. Of the 130 patients, 8 were homozygous FH patients and 38 were children. Of FH individuals, 46.7% was confirmed by genetic testing: 61 patients (96.8%) carried the LDLR mutation (c.681C > G, c.1427C > G, c.1187-?_2140 ± ?del, c.2529_2530delinsA), and two patients (3.2%) carried the PCSK9 (protein convertase subtilisin/kexin type 9) mutation (c.42_43insTG). The c.2529_2530delinsA mutation detected in this study is novel and reported only in the Vietnamese population. However, only 53.8% of FH patients were followed up post diagnosis, and only 15.3% of these were approved for lipid-lowering therapy and specialized care. Notably, factors such as knowledge about FH in patients and/or guardians of FH children and support of primary care physicians affected patient participation with respect to treatment strategies and follow-up. Genetic identification, screening, and treatment of FH were feasible in Vietnam. The VINAFH Registry significantly contributed to the formation of the government agencies legislative acts that established the importance of FH as a socially and medically important disease requiring appropriate management strategies. Other low- and middle-income countries could, thus, use the VINAFH Registry model as a reference to establish programs for FH management according to the current status.

Predictive biological patterns in Fabry disease revealed by integrative omics machine learning analysis

Protein convertase subtilisin kexin type 9 (PCSK-9) inhibitors demonstrated efficacy in cholesterol reduction and in the prevention of cardiovascular events. We evaluated changes in lipid profile and carotid stiffness in patients with familial hypercholesterolemia during 12 weeks of treatment with a PCSK-9 inhibitor, Evolocumab®.Patients with familial hypercholesterolemia starting a treatment with Evolocumab® were included. Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), small dense LDL (assessed by LDL score) and carotid stiffness were evaluated before starting treatment with Evolocumab® and during 12 weeks of treatment.Twenty-five subjects were enrolled (52% males, mean age 51.5 years). TC and LDL-C were reduced of 38% and 52%, respectively during treatment, with LDL score reduced of 46.1%. In parallel, carotid stiffness changed from 8.8 (IQR: 7.0–10.4) m/sec to 6.6 (IQR: 5.4–7.5) m/sec, corresponding to a median change of 21.4% (p < 0.001), with a significant increase in carotid distensibility (from 12.1, IQR: 8.73–19.3 kPA−1 × 10−3 at T0 to 21.8, IQR: 16.6–31.8 kPA−1 × 10−3 at T12w) corresponding to a median change of 62.8% (p < 0.001). A multivariate analysis showed that changes in LDL score were independently associated with changes in carotid stiffness (β = 0.429, p = 0.041).Small dense LDL reduction, as assessed by LDL score, is associated with changes in carotid stiffness in patients with familial hypercholesterolemia treated with Evolocumab®.

The relationship between protein convertase subtilisin kexin type-9 levels and extent of coronary artery disease in patients with non-ST-elevation myocardial infarction.

Cardiovascular disease is one of the leading causes of death worldwide. According to the results of various studies, protein convertase subtilisin kexin type-9 (PCSK9) was determined as a novel risk factor for stable coronary artery disease. Few studies have investigated the relationship between PCSK9 levels and the severity of coronary artery disease in patients with acute coronary syndrome; thus, we herein aimed to investigate this relationship in patients with non-ST-elevation myocardial infarction (NSTEMI) who underwent coronary angiography. Herein, 168 patients with NSTEMI were prospectively enrolled, and severity of atherosclerotic lesions was determined using SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery (SYNTAX), Gensini and Jeopardy scores. Plasma PCSK9 levels, lipid parameters and C-reactive protein levels were measured after a 12-h fasting period. The relationship of PCSK9 levels and clinical and laboratory parameters of patients with their SYNTAX, Gensini and Jeopardy scores was investigated. Pearson correlation analysis showed a strong positive correlation between PCSK9 and the three scores (P < 0.001, r > 0.5 for all). In ROC analysis, a mid-high SYNTAX score of at least 25 was predicted with a sensitivity of 81% and a specificity of 63% when the PCSK9 level was higher than 52.8 ng/ml (area under a curve 0.76, P < 0.001). Multivariate linear regression analysis revealed that PCSK9, low-density lipoprotein cholesterol and creatinine levels were independent predictors of a high SYNTAX score. Taken together, high PCSK9 levels may be a risk factor for adverse events in patients with NSTEMI. Aggressive lipid-lowering therapies may benefit this group of patients.

Protein convertase subtilisin/kexin type 9 biology in nephrotic syndrome: implications for use as therapy.

Low-density lipoprotein cholesterol (LDL-C) levels almost constantly increased in patients with nephrotic syndrome (NS). Protein convertase subtilisin/kexin type 9 (PCSK9) [accelerates LDL-receptor (LDL-R) degradation] is overexpressed by liver cells in NS. Their levels, correlated inversely to LDL-R expression and directly to LDL-C, seem to play a central role in hypercholesterolaemia in NS. Hypersynthesis resulting from sterol regulatory element-binding protein dysfunction, hyperactivity induced by c-inhibitor of apoptosis protein expressed in response to stimulation by tumour necrosis factor-α produced by damaged podocytes and hypo-clearance are the main possible mechanisms. Increased LDL-C may damage all kidney cell populations (podocytes, mesangial and tubular cells) in a similar manner. Intracellular cholesterol accumulation produces oxidative stress, foam cell formation and apoptosis, all favoured by local inflammation. The cumulative effect of cellular lesions is worsened proteinuria and kidney function loss. Accordingly, NS patients should be considered high risk and treated by lowering LDL-C. However, there is still not enough evidence determining whether lipid-lowering agents are helpful in managing dyslipidaemia in NS. Based on good efficacy and safety proved in the general population, therapeutic modulation of PCSK9 via antibody therapy might be a reasonable solution. This article explores the established and forthcoming evidence implicating PCSK9 in LDL-C dysregulation in NS.

Pharmacology of PCSK9 Inhibitors: Current Status and Future Perspectives.

Protein Convertase Subtilisin/Kexin type 9 (PCSK9) is a serine protease primarily expressed in the liver, which represents the main source of the plasma enzyme. The best characterized function of PCSK9 relates to the binding to Low-Density Lipoprotein Receptor (LDL-R) in hepatocytes, increasing its endosomal and lysosomal degradation. This results in the inhibition of LDL-R recycling to the cell surface and therefore the reduction of the hepatic uptake of LDL, leading to the increase in plasma levels of LDL-cholesterol, a major risk factor of Cardiovascular Diseases (CVD). Therefore, PCSK9 is an important therapeutic target to reduce LDLcholesterol levels. PCSK9 inhibition can occur at the level of its interaction with LDL-R as well as at several sites across the pathway of its intracellular synthesis and secretion. Two fully human mAbs, Alirocumab and Evolocumab, that selectively bind to PCSK9 and prevent its interaction with the LDL-R, are currently used in the clinical practice. These mAbs are the most potent cholesterol-lowering agents available today and can decrease LDLcholesterol levels up to 73% while they also reduce the risk of atherosclerotic CVD. Ongoing research has led to the development of new PCSK9 inhibitors through genome editing technology (CRISPR-Cas9), siRNA or antisense oligonucleotide silencing agents, vaccines, mimetic peptides, adnectins, and inhibitors of PCSK9 secretion. The above inhibitors have been studied in vitro, in animal models in vivo, as well as in phase I and II trials and have demonstrated an important efficacy profile. Future studies with these agents will demonstrate their possible clinical value and will further enlighten the various targets and activities of PCSK9 intracellularly and extracellularly, the underlying mechanisms, as well as the clinical significance of these actions beyond the inhibition of LDL-R recycling.

Two weeks of high-fat feeding disturb lipid and cholesterol molecular markers.

Metabolic disorders are often associated with liver steatosis and increased plasma cholesterol levels. However, the link between excessive lipid accumulation and impairments in cholesterol metabolism remains uninvestigated in the liver. Short term of high-fat diet (HFD) was previously shown to promote excessive lipid accumulation prior to the development of metabolic disorders. The present study intended to characterize how increases in liver fat alter the expression of several key regulators of hepatic cholesterol metabolism in response to a short-term HFD. Wistar rats were randomly submitted either to HFD (n=8) or a regular chow diet (n=8) for 14days. Increases in triglycerides were highly significant (P<0.01) in the liver but marginal in the plasma of HFD rats. In contrast, the HFD resulted in higher (P<0.01) cholesterol levels in plasma but not in liver samples. Gene expression of key markers involved in cholesterol uptake (LDL particles) including low-density lipoprotein receptor-related protein-1 (LRP-1) and protein convertase subtilisin/kexin type 9 (PCSK9) along with ATP-binding cassette, superfamily G, member 5 (ABCG5) involved in cholesterol exportation via bile ducts was found to be higher (P<0.05) in response to the HFD. In contrast, expression of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), involved in cholesterol synthesis, was downregulated in the liver. The data support the concept that excessive accumulation of lipids promptly alters the expression of key genes regulating cholesterol metabolism in the liver. On a clinical point of view, this indicates that increases in plasma cholesterol occur after a short-term HFD.

PL-006 Expression of molecular markers of hepatic cholesterol metabolism are altered by a short-term high-fat diet

Objective Metabolic disorders are often associated with liver steatosis and increased plasma cholesterol levels. However, the link between excessive lipid accumulation and impairments in cholesterol metabolism remains uninvestigated in the liver. Hence, a short treatment with a high-fat diet (HFD) was previously shown to promote excessive lipid accumulation in liver prior to the development of metabolic disorders. The present study intended to characterize how increases in liver fat alter the expression of several key regulators of hepatic cholesterol metabolism in response to a short-term HFD.&#x0D; Methods Young Wistar rats were randomly submitted either to HFD (n = 8) or a regular chow diet (RCD; n = 8) for 14 days.Liver tissue and blood were sampled .&#x0D; Results Increases in triglycerides were highly significant (P&lt; 0.01) in liver but marginal in plasma of HFD rats. In contrast, the HFD resulted in higher (P&lt; 0.01) cholesterol levels in plasma but not in liver samples. Gene expression of key markers involved in cholesterol uptake (LDL particles) including low density lipoprotein receptor-related protein-1 (LRP-1) and protein convertase subtilisin/kexin type 9 (PCSK9) along with ATP-binding cassette, superfamily G, member 5 (ABCG5) involved in cholesterol exportation viabile ducts were found to be higher (P&lt; 0.05) in response to the HFD. In contrast, expression of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), involved in cholesterol synthesis was down-regulated in liver&#x0D; Conclusions The data support the concept that excessive accumulation of lipids promptly alters the expression of key genes regulating cholesterol metabolism in liver. On a clinical point of view, this indicates that increases in plasma cholesterol occur after a short-term high fat diet.

PCSK9 Inhibitor causes a decrease in the level of oxidatively modified low-density lipoproteins in patients with coronary artery diseases.

We study the dynamics of oxidatively modified low-density lipoprotein (ox-LDL) content in blood plasma, as well as changes in the activity of key antioxidant enzymes such as Se-containing glutathione peroxidase (GSH-Px) Cu,Zn-superoxide dismutase (SOD) and catalase in erythrocytes of patients with coronary artery disease during treatment with PCSK9 inhibitor (ewolocumab). The study included 9 men (59 ± 10 years) with coronary artery disease with atherosclerotic lesion at least one main coronary artery according to coronary angiography. Patients took standard therapy before taking the study, everyone took the maximum tolerated dose of statins. Since the target cholesterol levels of low-density lipoprotein cholesterol (LDL-C) were not achieved during the statin therapy, patients were prescribed lipid-lowering therapy with the inclusion of the inhibitor PCSK9-emocoucumab from Amgen 420 mg once a month. The content of lipid metabolism indices was determined by standard biochemical methods. The level of ox-LDL in the blood plasma was determined by the immunochemical method. The activity of antioxidant enzymes was determined in blood erythrocytes using biochemical techniques. Cholesterol-lowering drug of the new type - inhibitor protein convertase subtilisin/kexin type 9 (PCSK9) evolocumab (Amgen) not only effectively lowers the level of cholesterol in low density lipoprotein (LDL), but also significantly reduces the content of oxdatively modified LDL in blood plasma. Unlike statins, the inhibitor of PCSK9 does not cause a decrease in the activity of antioxidant enzymes of the blood. PCSK9 inhibitor has no effect on the parameters of oxidative stress.

PCSK9 inhibitors in clinical practice: Delivering on the promise?

Background and aimsIn clinical trials, protein convertase subtilisin/kexin type 9 (PCSK9) inhibitors robustly lowered LDL-cholesterol (LDL-c) and had a favorable tolerability and safety profile. Based on these findings, PCSK9 inhibitors are incorporated in updates of clinical treatment guidelines. However, trial results do not necessarily predict the effectiveness under real-world conditions. The aim of the current study is to determine the efficacy and tolerability of PCSK9 inhibitors in routine outpatient care. MethodsThe cohort comprised all patients who were prescribed evolocumab or alirocumab at the outpatient clinic of a large university hospital in the Netherlands. Eligible patients required additional lipid-lowering despite maximally tolerated statin therapy and ezetimibe, or were statin intolerant. Data were systematically collected during routine outpatient visits. ResultsThe study included 238 patients of whom 67.2% had familial hypercholesterolemia (FH) and 42.9% were statin intolerant. The mean LDL-c reduction was 55.0% from a baseline of 4.4 mmol/L. LDL-c goals were attained by 62.3% of patients. Side effects were reported by 15.5% of patients and 2.5% discontinued treatment. No meaningful differences in efficacy or tolerability were observed between patients with FH or statin intolerance, or across treatment regimens. ConclusionsThe observed lipid reductions and side effects profile of PCSK9 inhibitors in a routine care setting were comparable to observations in clinical trials.