Plasma Proprotein Convertase Subtilisin/kexin Type 9 Research Articles

Association Between Plasma Proprotein Convertase Subtilisin/Kexin Type 9 and the Presence of Metabolic Syndrome in a Predominantly Rural-Based Sub-Saharan African Population.

The prevalence of metabolic syndrome (MetS) has increased dramatically in low- and middle-income countries. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a major role in low-density lipoprotein receptor degradation, but its relationship with metabolic parameters is still poorly understood. We aimed to investigate the association between plasma PCSK9 and metabolic parameters in a Kenyan cohort. Total plasma PCSK9 levels were measured in 2016 by an in-house enzyme-linked immunosorbent assay (ELISA) using a polyclonal antibody. The International Diabetes Federation (IDF) 2009 consensus statement criteria were used to assess the presence of MetS. In 1338 Kenyans, 11% of the cohort had ≥3 MetS criteria. Total plasma PCSK9 concentration was significantly higher in subjects with MetS than in the non-MetS group (166.8 ± 4.4 vs. 148.0 ± 1.3, P < 0.0001). A progressive increase in circulating PCSK9 was observed when subjects were stratified according to the number of MetS criteria (<3, 3, 4, or 5) [P of the analysis of variance (ANOVA) <0.0001]. In a model corrected for age, sex, lifestyle factors, and body mass index, PCSK9 concentration was a significant predictor of all MetS criteria taken individually, except for waist circumference. Plasma PCSK9 levels were significantly associated with low-density lipoprotein cholesterol, but the strongest association was seen with triglycerides even after multiple adjustments. The presence of MetS was significantly associated with the PCSK9 concentration. Further studies are needed to provide a molecular connection between PCSK9 and insulin, as well as triglyceride metabolism.

In Vivo Base Editing of PCSK9 (Proprotein Convertase Subtilisin/Kexin Type 9) as a Therapeutic Alternative to Genome Editing.

High-efficiency genome editing to disrupt therapeutic target genes, such as PCSK9 (proprotein convertase subtilisin/kexin type 9), has been demonstrated in preclinical animal models, but there are safety concerns because of the unpredictable nature of cellular repair of double-strand breaks, as well as off-target mutagenesis. Moreover, precise knock-in of specific nucleotide changes-whether to introduce or to correct gene mutations-has proven to be inefficient in nonproliferating cells in vivo. Base editors comprising CRISPR-Cas9 (clustered regularly interspaced short palindromic repeats [CRISPR]-CRISPR-associated 9) fused to a cytosine deaminase domain can effect the alteration of cytosine bases to thymine bases in genomic DNA in a sequence-specific fashion, without the need for double-strand DNA breaks. The efficacy of base editing has not been established in vivo. The goal of this study was to assess whether in vivo base editing could be used to modify the mouse Pcsk9 gene in a sequence-specific fashion in the liver in adult mice. We screened base editors for activity in cultured cells, including human-induced pluripotent stem cells. We then delivered a base editor into the livers of adult mice to assess whether it could introduce site-specific nonsense mutations into the Pcsk9 gene. In adult mice, this resulted in substantially reduced plasma PCSK9 protein levels (>50%), as well as reduced plasma cholesterol levels (≈30%). There was no evidence of off-target mutagenesis, either cytosine-to-thymine edits or indels. These results demonstrate the ability to precisely introduce therapeutically relevant nucleotide variants into the genome in somatic tissues in adult mammals, as well as highlighting a potentially safer alternative to therapeutic genome editing.

Circulating PCSK9 affects serum LDL and cholesterol levels more than SREBP-2 expression.

Cholesterol homeostasis is dependent upon the sterol regulatory element binding protein 2 (SREBP-2) regulatory system and the functioning of plasma proprotein convertase subtilisin/kexin type 9 (PCSK9). Many studies have also reported that low density lipoprotein receptor (LDLR) levels in cellular membranes are related to the functioning of these proteins. The aim of this study was to investigate the association of lipid profiles with circulating PCSK9 protein values and SREBP-2 expression levels in normal subjects. The study involved 120 randomly chosen healthy subjects. Their lipid profiles were measured using routine laboratory techniques, and the plasma PCSK9 protein and SREBP-2 expression levels were determined by ELISA and real time quantitative PCR methods, respectively. A statistical analysis was carried out using a statistical software package. Linear regression analyses showed a significant correlation between total cholesterol and PCSK9 (3.54 ± 1.31 ng/mL), as well as between total cholesterol and SREBP-2 (0.1-35.38) (p = 0.002 and p = 0.02, respectively). Furthermore, multiple regression analyses showed strict correlations between PCSK9 and cholesterol-related parameters especially the total cholesterol/HDL-C ratio (β = 3.53, p = 0.001). There was no significant correlation between circulating PCSK9 and SREBP-2 expression levels (r = 1.2, p = 0.3). The study results revealed that serum cholesterol-related parameters are strictly associated with plasma PCSK9 values, suggesting that PCSK9 function has a greater effect on serum total cholesterol levels than SREBP-2 expression does. Furthermore, the total cholesterol/HDL-C ratio was a better indicator for evaluating PCSK9 level than total cholesterol.

Association between plasma proprotein convertase subtisilin/kexin type 9 concentration and coronary artery calcification.

Background Plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) has been reported to be related to several risk factors and diseases such as inflammatory markers and coronary artery disease. The aim of present study was to investigate whether plasma PCSK9 concentration was associated with coronary artery calcification. Methods A total of 403 consecutive untreated patients with angina-like chest pain, who received electron beam computed tomography, were enrolled and a coronary artery calcification score (CACS) was also measured. The baseline clinical characteristics were collected and blood sample was taken after 12-h fasting. The plasma PCSK9 concentrations were determined by ELISA in all patients, and the relationship between plasma PCSK9 concentrations and CACS was investigated. Results Patients with coronary artery calcification (CACS > 0) had significant higher plasma PCSK9 concentrations compared with those (CACS = 0) without coronary artery calcification (258.58 ± 69.53 ng/mL vs. 202.53 ± 52.17 ng/mL, P < 0.001). Patients with highest PCSK9 concentrations had the highest CACS. Multivariable linear regression analysis suggested that PCSK9 was independently associated with coronary artery calcification ( P = 0.002) after adjusting for traditional cardiovascular risk factors. Furthermore, the area under the curve for the plasma PCSK9 concentration in predicting coronary artery calcification was 0.736 (95% CI: 0.687-0.785, P < 0.001), with a sensitivity of 66% and specificity of 70%. Conclusion A positive association between plasma PCSK9 concentration and coronary artery calcification in untreated patients with angina-like chest pain was observed in our study, suggesting that further investigation may be needed in order to confirm our primary findings and explore the clinical implications.

CAT-2003: A novel sterol regulatory element-binding protein inhibitor that reduces steatohepatitis, plasma lipids, and atherosclerosis in apolipoprotein E*3-Leiden mice.

CAT‐2003 is a novel conjugate of eicosapentaenoic acid (EPA) and niacin designed to be hydrolyzed by fatty acid amide hydrolase to release EPA inside cells at the endoplasmic reticulum. In cultured liver cells, CAT‐2003 blocked the maturation of sterol regulatory element‐binding protein (SREBP)‐1 and SREBP‐2 proteins and decreased the expression of multiple SREBP target genes, including HMGCR and PCSK9. Consistent with proprotein convertase subtilisin/kexin type 9 (PCSK9) reduction, both low‐density lipoprotein receptor protein at the cell surface and low‐density lipoprotein particle uptake were increased. In apolipoprotein E*3‐Leiden mice fed a cholesterol‐containing western diet, CAT‐2003 decreased hepatic inflammation and steatosis as evidenced by fewer inflammatory cell aggregates in histopathologic sections, decreased nuclear factor kappa B activity in liver lysates, reduced inflammatory gene expression, reduced intrahepatic cholesteryl ester and triglyceride levels, and decreased liver mass. Plasma PCSK9 was reduced and hepatic low‐density lipoprotein receptor protein expression was increased; plasma cholesterol and triglyceride levels were lowered. Aortic root segments showed reduction of several atherosclerotic markers, including lesion size, number, and severity. CAT‐2003, when dosed in combination with atorvastatin, further lowered plasma cholesterol levels and decreased hepatic expression of SREBP target genes. Conclusion: SREBP inhibition is a promising new strategy for the prevention and treatment of diseases associated with abnormal lipid metabolism, such as atherosclerosis and nonalcoholic steatohepatitis. (Hepatology Communications 2017;1:311–325)

Abstract 197: Characterization of the Effects of Angiopoietin-Like 3 on Plasma Lipids and Lipoproteins in Humans

Angiopoietin-like 3 (ANGPTL3) deficiency due to loss-of-function (LOF) gene mutations causes familial combined hypobetalipoproteinemia type 2 (FHBL2) in homozygotes and compound heterozygotes, with a lipid phenotype much milder in heterozygotes. We aim to determine whether a critical reduction in plasma ANGPTL3 levels is a major determinant of FHBL2 lipid phenotype. We studied 126 subjects from 19 families with ANGPTL3 LOF mutations. Individuals homozygous for mutations in ANGPTL3 manifest the full FHBL2 phenotype of reduced total cholesterol, triglycerides, very low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol (-C) and particle concentration (-p), and LDL size. Heterozygotes only displayed with low total cholesterol, HDL-C, HDL-p and VLDL-p compared with non-carriers. Using multivariate adaptive regression splines, we found that: ( i ) total cholesterol, triglycerides, LDL-C, HDL-C, HDL-p, and LDL size correlated with ANGPTL3 but only for levels below 25% of normal (&lt;60 ng/dl); ( ii ) VLDL-p and LDL-p correlate with ANGPTL3 irrespective of its plasma levels; and ( iii ) homozygotes exhibited reduced levels of mature proprotein convertase subtilisin/kexin type 9 (PCSK9), a known regulator of plasma LDL-C levels. These results indicate that the full FHBL2 phenotype seen in homozygous carriers of LOF mutations in ANGPTL3 is caused by a critical reduction of more than 75% of its plasma levels, thus uncovering the relationship between mutation status, plasma ANGPTL3 concentrations, and the lipid phenotype. Furthermore, our study suggests that the low plasma LDL seen in homozygous carriers of ANGPTL3 LOF mutations is mediated by the modulation of plasma PCSK9.

Selective stalling of human translation through small-molecule engagement of the ribosome nascent chain.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a key role in regulating the levels of plasma low-density lipoprotein cholesterol (LDL-C). Here, we demonstrate that the compound PF-06446846 inhibits translation of PCSK9 by inducing the ribosome to stall around codon 34, mediated by the sequence of the nascent chain within the exit tunnel. We further show that PF-06446846 reduces plasma PCSK9 and total cholesterol levels in rats following oral dosing. Using ribosome profiling, we demonstrate that PF-06446846 is highly selective for the inhibition of PCSK9 translation. The mechanism of action employed by PF-06446846 reveals a previously unexpected tunability of the human ribosome that allows small molecules to specifically block translation of individual transcripts.

A New Approach to PCSK9 Therapeutics.

PCSK9 inhibition is an effective therapy to reduce LDL cholesterol (LDL-C) and cardiovascular events. A recent study shows that one or two doses of inclisiran, a long-acting synthetic small-interfering RNA (siRNA) that selectively targets hepatic PCSK9, causes a sustained reduction of plasma LDL-C for up to 6 months. Pending further studies of safety and efficacy, this may represent an important addition to the armamentarium for inhibiting PCSK9.

Plasma PCSK9 measurement by liquid chromatography-Tandem mass spectrometry and comparison with conventional ELISA.

The combination of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and trypsin proteolysis is an effective tool for accurate quantitation of multiple proteins in a single run. However, expensive samples pre-treatment as immunoenrichment are often required to analyze low abundant proteins. Plasma proprotein convertase subtilisin/kexin type 9 (PCSK9), a circulating regulator of low-density lipoprotein metabolism, was studied as an example of a low abundant plasma protein. We investigated post-proteolysis solid-phase extraction (SPE) as an alternative strategy to improve its detection. After optimization of pretreatment, including denaturation, reduction, alkylation, tryptic digestion and selective SPE concentration, 91±7% of PCSK9 was recovered from human plasma samples and coefficients of variation were less than 13.2% with a lower limit of quantification of 37.5ng/ml. This LC-MS/MS method was compared with standard enzyme-linked immunosorbent assay in 30 human plasma samples with a broad range of PCSK9 concentrations. Both methods were significantly correlated (r=0.936, p<0.001) with less than 7% of the values out of the 95% confidence interval and similar concentrations were measured using either LC-MS/MS or ELISA methods (514.2±217.2 vs. 504.2±231.0ng/ml, respectively- p=NS). This method involving SPE is an effective measurement tool for low abundant plasma protein analysis that could be easily included in multiplexed assays.

Comparing expression and activity of PCSK9 in SPRET/EiJ and C57BL/6J mouse strains shows lack of correlation with plasma cholesterol

ObjectiveLow-density lipoprotein receptor (LDLR) and proprotein convertase subtilisin/kexin type 9 (PCSK9) are opposing regulators of plasma LDL-cholesterol levels. The PCSK9 gene exhibits many single or compound polymorphisms within or among mammalian species. This is case between the SPRET/EiJ (SPRET) and C57BL/6J (B6) mouse strains. We examined whether these polymorphisms could be associated with differential expression and activity of their respective PCSK9 molecules. MethodsLiver expression of LDLR and PCSK9 transcripts were assessed by RT-PCR, and that of their corresponding proteins by immunoblotting. Purified recombinant PCSK9 proteins were assayed for their ability to degrade LDLR. Pcsk9 gene proximal promoters were tested for activation of a luciferase reporter gene. ResultsSPRET and B6 mice carried comparable levels of plasma cholesterol in spite of the fact that SPRET mice expressed less PCSK9 and more LDLR in liver. There were indels and single-base differences between their Pcsk9 cDNA and promoter sequences. Ex vivo, SPRET PCSK9 protein was less secreted but was more active at degrading LDLR. Its gene promoter was more active at driving expression of the luciferase reporter. ConclusionsCollectively, these results suggest that, compared to the B6 mouse, the SPRET mouse may represent an example of absence of direct correlation between PCSK9 and cholesterol levels in plasma, due to genetic variations leading to reduced secretion of PCSK9 associated with greater LDLR-degrading activity.

Glycaemic control influences the relationship between plasma PCSK9 and LDL cholesterol in type 1 diabetes.

Pro-protein convertase subtilisin/kexin type 9 (PCSK9) is a critical regulator of LDL cholesterol metabolism. Little is known, however, about the regulation of PCSK9 in patients with type 1 diabetes (T1D). In the present study, we aimed to determine the relationship between circulating PCSK9 and metabolic variables in T1D. Plasma PCSK9 levels were measured in 195 people with T1D (mean age 38.8 years, mean diabetes duration 17.2 years, mean glycated haemoglobin [HbA1c] 8.3%), who were free of any lipid-lowering agent. Plasma PCSK9 was positively correlated with LDL cholesterol (P = .0007), triglycerides (P = .004), apolipoprotein B (P = .005), HbA1c (P = .003), systolic (P = .003) and diastolic (P = .001) blood pressure and body mass index (0.02). In multivariate analysis, PCSK9 concentration was independently associated with HbA1c (P = .02) and LDL cholesterol (P = .03). After classifying patients according to HbA1c tertile, the correlation between PCSK9 and LDL cholesterol was only observed in the highest tertile (P = .0006; Rho = 0.43), whereas no correlation was found in the lowest and intermediate tertiles. This study suggests that good glycaemic control abolishes the positive relationship between PCSK9 and LDL cholesterol in patients with T1D; however, the underlying molecular mechanisms remain to be established.

Plasma PCSK9 concentrations during the course of nondiabetic chronic kidney disease: Relationship with glomerular filtration rate and lipid metabolism

The association between proprotein convertase subtilisin/kexin type 9 (PCSK9), a critical regulator of low-density lipoprotein (LDL) metabolism, and kidney function is a matter of debate. We aimed to assess the association of circulating PCSK9 concentrations with both glomerular filtration rate (eGFR) and serum lipid parameters in nondiabetic patients with chronic kidney disease (CKD). Fasting plasma PCSK9 concentrations were measured by ELISA in 94 nondiabetic nondialysis CKD (ND-CKD) patients not receiving statins, at different stages of CKD. Plasma PCSK9 levels were associated neither to eGFR (P=.770) nor to proteinuria (P=.888) at several stages of CKD. In addition, plasma PCSK9 levels did not vary significantly between the different CKD stages. Plasma PCSK9 concentrations were positively correlated with apolipoprotein B (r=0.221; P=.03) and triglycerides (r=0.211; P=.04) but not with total cholesterol, calculated LDL-cholesterol, HDL cholesterol, lipoprotein(a), or CRP. In a homogeneous population of nondiabetic subjects without lipid-lowering therapy, plasma PCSK9 concentrations are not associated to eGFR at several stages of CKD. These data suggest that kidney function per se does not impact significantly PCSK9 metabolism.

Novel circulating lipid measurements for current dyslipidemias in non-treated patients undergoing coronary angiography: PCSK9, apoC3 and sdLDL-C.

Plasma levels of proprotein convertase subtilisin/kexin type 9 (PCSK9), apolipoprotein C-III (apoC3) and small dense low density lipoprotein cholesterol (sdLDL-C), have been recently recognized as circulating atherosclerosis-related lipid measurements. We aimed to elucidate their associations with current dyslipidemias, and identify their levels at increased risk to dyslipidemia. A total of 1,605 consecutive, non-treated patients undergoing diagnostic/interventional coronary angiography were examined. Plasma PCSK9 and apoC3 levels were determined using a validated ELISA assay, and sdLDL-C was measured by the Lipoprint LDL System. Plasma levels of PCSK9, apoC3, and sdLDL-C were associated with the current dyslipidemias classification (all p<0.001). PCSK9 significantly conferred prediction of both hypercholesterolemia and combined hyperlipidemia at a level of 235 ng/ml; apoC3 levels for hypertriglyceridemia, hypercholesterolemia and combined hyperlipidemia were 80.0, 71.5, and 86.4 g/ml, respectively; and sdLDL-C for hypertriglyceridemia, hypercholesterolemia, combined hyperlipidemia and hypo high density lipoprotein (HDL) cholesterolemia 3.5, 2.5, 4.5, and 2.5 mg/dl, respectively (all p<0.001 for area under the receiver-operating characteristic curve). In a polytomous logistic model comparing increasing LDL-C categories, the interactions with high PCSK9, apoC3, and sdLDL-C elevated gradually. Similarly, apoC3 and sdLDL-C showed elevated interaction with increased triglyceride categories, and only sdLDL-C showed interaction with decreased HDL cholesterol (HDL-C) categories. Furthermore, discordances of PCSK9, apoC3, and sdLDL-C with current dyslipidemias were observed. PCSK9, apoC3, and sdLDL-C showed significant interactions with current dyslipidemias, and were predictive in the screening. The substantial discordances with current dyslipidemias might provide novel view in lipid management and further cardiovascular benefit.

Predicting proprotein convertase subtilisin kexin type-9 loss of function mutations using plasma PCSK9 concentration

Low plasma proprotein convertase subtilisin kexin type-9 (PCSK9) concentration has been associated with loss of function (LOF) PCSK9 mutations in several studies. However, the current standard for detection of these LOF mutations is through gene sequencing. Gene sequencing is labor intensive and expensive. Identifying a simple test to help predict PCSK9 LOF mutations would help to better target subjects requiring gene sequencing. Determine the diagnostic accuracy of plasma PCSK9 concentration in detecting PCSK9 LOF mutations using genotyping as the gold standard. We carried out a retrospective analysis of 1412 French-Canadian participants of the Quebec Child and Adolescent Health and Social Survey who had been screened for the PCSK9 R46L and Leucine insertion (InsLEU) LOF mutations by genotyping. Their plasma PCSK9 concentrations were measured using a well-described enzyme-linked immunosorbent assay. We used the Youden index to determine the optimal cutoff for PCSK9 concentration to predict mutation status. We further investigated the use of low-density lipoprotein cholesterol (LDL-C) concentration in combination with plasma PCSK9 concentration to refine the prediction of mutation status. Plasma PCSK9 had a moderate accuracy (area under the curve, 0.71) in detecting the PCSK9 R46L mutation with a sensitivity of 71% and specificity of 70% at cutoff of 70ng/mL. Combining PCSK9 and LDL-C increased the diagnostic accuracy for the detection of the R46L mutation (area under the curve, 0.75). However, plasma PCSK9 concentration was no better than chance at detecting PCSK9 InsLEU mutation. This analysis suggests that plasma PCSK9 combined with LDL-C concentrations might be useful to predict certain PCSK9 LOF mutations such as the R46L mutation but may fail to predict others such as the InsLEU mutation.

Impact of a 1-year lifestyle modification program on plasma lipoprotein and PCSK9 concentrations in patients with coronary artery disease

Patients with coronary artery disease (CAD) are characterized by an impaired cardiometabolic risk profile including high levels of atherogenic apolipoprotein (apo) B-containing lipoprotein levels. Genetic studies have highlighted a critical role for proprotein convertase subtilisin/kexin type 9 (PCSK9) in lipoprotein metabolism and CAD risk. To determine whether improving dietary quality and increasing physical activity levels improve parameters of the cardiometabolic risk profile such as plasma apoB and PCSK9 levels in patients with CAD. We recruited 86 men aged between 39 and 80years (82 of them on statins) undergoing coronary artery bypass graft (CABG) surgery. These patients participated in a 1-year lifestyle modification program aiming at achieving a minimum of 150minutes/week of physical activity and improving diet quality by following dietary guidelines. We used magnetic resonance imaging to measure visceral adipose tissue and a modified Bruce protocol to measure fitness levels before and after the intervention. Plasma apoB and low-density lipoprotein cholesterol levels were not modified by the intervention (-3.0%, P=.08 and 1.3%, P=.56, respectively), whereas non-HDL cholesterol decreased by 4.5% (P=.04) and triglycerides by 13% (P=.002). In contrast, PCSK9 levels increased by 5.2% after the intervention (P=.05). HDL cholesterol and apolipoprotein A-I levels also increased (+12%, P<.0001 and+6%, P<.0001, respectively). PCSK9 levels increased with improvements in fitness (r=0.23, P=.04) and visceral fat mobilization (r=-0.23, P=.04). In post-CABG patients, a lifestyle modification program lead to significant improvements in some parameters of the lipoprotein profile but unexpectedly increased plasma PCSK9 levels.

PCSK9 in diabetic kidney disease.

Chronic Kidney Disease (CKD) and, specifically, diabetic kidney disease (DKD)+, is among the fastest increasing causes of death worldwide. A better understanding of the factors contributing to the high mortality may help design novel monitoring and therapeutic approaches, since protection offered by statins in CKD patients is not satisfactory. Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) promotes hypercholesterolemia and may be targeted therapeutically. Adding anti-PCSK9 agents to standard lipid lowering therapy further reduces the incidence of cardiovascular events. We studied plasma PCSK9 in a cross-sectional study of 134 diabetic kidney disease patients with estimated glomerular filtration rate (eGFR) categories G1-G4 and albuminuria categories A1-A3, in order to identify factors influencing plasma PCSK9 in this population. Mean±SD plasma PCSK9 levels were 309.8±113.9 ng/ml. Plasma PCSK9 was not influenced by eGFR or albuminuria, but was higher in patients on lipid lowering therapy. In univariate analysis, plasma PCSK9 showed a significant positive correlation with serum total iron binding capacity, vitamin E, plasma renin and phosphaturia, and there was a trend towards a positive correlation with total serum cholesterol. In multivariate models, only therapy with fibrate and statin, and renin remained independently correlated with plasma PCSK9. However, multivariate models explained very little of the PCSK9 variability. In DKD, therapy with lipid lowering drugs and specially the fibrate/statin combination were independently associated with higher PCSK9 levels. The biomarker potential of PCSK9 levels to identify DKD patients that may benefit from anti-PCSK9 strategies should be studied.

Proprotein convertase subtilisin/kexin type 9 levels and aortic valve calcification: A prospective, cross sectional study.

ObjectiveTo investigate the possible association between plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) and the incidence and severity of calcific aortic valve disease (CAVD).MethodsThis prospective, cross sectional study involved patients with and without (controls) aortic valve calcification diagnosed by transthoracic echocardiography and dual source computed tomography (DSCT) scan. Aortic valves calcification scores were calculated from DSCT scans and patients were graded: grade 1, no calcification; grade 2, mildly calcified; grade 3, moderately calcified; grade 4, heavily calcified. Plasma PCSK9 levels were measured using an enzyme-linked immunosorbent assay.ResultsForty patients were grade 1 (controls), 32 were grade 2, 48 were grade 3 and 32 were grade 4. Plasma levels of PCSK9 were significantly different between the four groups and the highest value was observed in the patients with grade 2 calcification. Only low-density lipoprotein cholesterol and lipoprotein (Lp)(a) were associated with the severity of CAVD. Regression analysis showed that age, Lp(a) and PCSK9 were independent predictors of CAVD.ConclusionData from this cross sectional study in a small sample of patients showed that plasma PCSK9 was correlated with the presence of CAVD but not its severity.

Dietary high oleic canola oil supplemented with docosahexaenoic acid attenuates plasma proprotein convertase subtilisin kexin type 9 (PCSK9) levels in participants with cardiovascular disease risk: A randomized control trial

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a novel circulating protein which plays an important role in regulation of cholesterol metabolism by promoting hepatic LDL receptor degradation. However, the action of dietary fat composition on PCSK9 levels remains to be fully elucidated. The objective was to investigate the action of different dietary oils on circulating PCSK9 levels in the Canola Oil Multicenter Intervention Trial (COMIT). COMIT employed a double-blinded crossover randomized control design, consisting of five 30-d treatment periods. Diets were provided based on a 3000Kcal/d intake, including a 60g/d treatment of conventional canola oil (Canola), a high oleic canola/DHA oil blend (CanolaDHA), a corn/safflower oil blend (CornSaff), a flax/safflower oil blend (FlaxSaff) or a high oleic canola oil (CanolaOleic). Plasma PCSK9 levels were assessed using ELISA at the end of each phase. Lipid profiles (n=84) showed that CanolaDHA feeding resulted in the highest (P<0.05) serum total cholesterol (TC, 5.06±0.09mmol/L) and LDL-cholesterol levels (3.15±0.08mmol/L) across all five treatments. CanolaDHA feeding also produced the lowest (P<0.05) plasma PCSK9 concentrations (216.42±8.77ng/mL) compared to other dietary oil treatments. Plasma PCSK9 levels positively correlated (P<0.05) with serum TC, LDL-cholesterol, apolipoprotein A, and apolipoprotein B levels but did not correlate to HDL-cholesterol levels. Results indicate that post-treatment response in PCSK9 may be altered with the CanolaDHA diet. In conclusion, the elevated LDL-C levels from a DHA oil treatment may not be relevant for the observed decline in PCSK9 levels.

The Role of Proprotein Convertase Subtilisin/Kexin Type 9 in Nephrotic Syndrome-Associated Hypercholesterolemia.

In nephrotic syndrome, damage to the podocytes of the kidney produces severe hypercholesterolemia for which novel treatments are urgently needed. PCSK9 (proprotein convertase subtilisin/kexin type 9) has emerged as an important regulator of plasma cholesterol levels and therapeutic target. Here, we tested the role of PCSK9 in mediating the hypercholesterolemia of nephrotic syndrome. PCSK9 and plasma lipids were studied in nephrotic syndrome patients before and after remission of disease, mice with genetic ablation of the podocyte (Podocyte Apoptosis Through Targeted Activation of Caspase-8, Pod-ATTAC mice) and mice treated with nephrotoxic serum (NTS), which triggers immune-mediated podocyte damage. In addition, mice with hepatic deletion of Pcsk9 were treated with NTS to determine the contribution of PCSK9 to the dyslipidemia of nephrotic syndrome. Patients with nephrotic syndrome showed a decrease in plasma cholesterol and plasma PCSK9 on remission of their disease (P<0.05, n=47-50). Conversely, Pod-ATTAC mice and NTS-treated mice showed hypercholesterolemia and a 7- to 24-fold induction in plasma PCSK9. The induction of plasma PCSK9 appeared to be attributable to increased secretion of PCSK9 from the hepatocyte coupled with decreased clearance. Interestingly, knockout of Pcsk9ameliorated the effects of NTS on plasma lipids. Thus, in the presence of NTS, mice lacking hepatic Pcsk9 showed a 40% to 50% decrease in plasma cholesterol and triglycerides. Moreover, the ability of NTS treatment to increase the percentage of low-density lipoprotein-associated cholesterol (from 9% in vehicle-treated Flox mice to 47% after NTS treatment), was lost in mice with hepatic deletion of Pcsk9 (5% in both the presence and absence of NTS). Podocyte damage triggers marked inductions in plasma PCSK9, and knockout of Pcsk9 ameliorates dyslipidemia in a mouse model of nephrotic syndrome. These data suggest that PCSK9 inhibitors may be beneficial in patients with nephrotic syndrome-associated hypercholesterolemia.

Positive correlation between plasma PCSK9 and tissue factors levels in patients with angiographically diagnosed coronary artery disease and diabetes mellitus.

BackgroundPro-protein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that influences plasma levels of low-density lipoprotein cholesterol (LDL-C). Both oxidized LDL and tissue factor (TF) contributed to the development of prothrombotic state. The present study aims to explore the relationship between plasma level of PCSK9 and that of TF in patient with coronary artery disease (CAD).MethodsFrom July 2013 to March 2014, we enrolled 197 consecutive patients who underwent coronary angiography because of suspected CAD at Beijing Anzhen Hospital in this study. All patients had no history of using lipid-lowering medication. Of these 197 patients (131 male and 66 female, mean age 56.9 ± 11.8 years), 81 had angiographically diagnosed CAD. Clinical data were collected. Plasma PCSK9 and TF were measured using enzyme-linked immunosorbent assay (ELISA). Levels of plasma PCSK9 and TF were compared and their correlation analyzed among different patient groups.ResultsBoth plasma levels of PCSK9 (279.8 ± 60.4 µg/L vs. 216.5 ± 45.3 µg/L, P < 0.01) and TF (156.4 ± 26.6 µg/mL vs. 112.1 ± 38.3 µg/L, P < 0.01) were significantly higher in patients with CAD, as compared with those without CAD. Correlation analysis showed plasma level of PCSK9 was significantly correlated with that of TF in both patients with and without CAD. However, multivariate regression analysis after adjustment for age, gender, smoking, alcohol, hypertension and hyperlipidemia showed that only in CAD patients with type 2 diabetes mellitus, there was significant positive correlation between plasma levels of PCSK9 and TF (β = 0.353, P < 0.01).ConclusionsThe plasma level of PCSK9 is independently and positively associated with that of TF in CAD patients with diabetes mellitus, but not in those without diabetes mellitus. Further study is needed to investigate the underlying mechanism.