Plasma Plasma Proprotein Convertase Subtilisin/kexin Type 9 Research Articles

Plasma Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) as a Possible Biomarker for Severe COVID-19.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) reduces low density lipoprotein (LDL) uptake, leading to increased plasma levels of LDL. In addition, PCSK9 has been implicated in inflammation independently of the effects on cholesterol metabolism. The current analysis showed that our 156 patients with systemic inflammatory response syndrome (SIRS) or sepsis had higher plasma PCSK9 levels in contrast with the 68 healthy controls. COVID-19 sepsis patients had increased plasma PCSK9 levels in comparison to sepsis patients not infected by SARS-CoV-2. For further analysis, patients were divided in two groups based on COVID-19. In both sub-cohorts, plasma PCSK9 levels did not correlate with C-reactive protein, leukocyte count, and procalcitonin. Plasma PCSK9 levels of both patient groups did not significantly differ among SIRS/sepsis patients with and without dialysis and patients with and without ventilation. Furthermore, vasopressor therapy was not significantly associated with altered plasma PCSK9 levels. In the non-COVID-19 SIRS/sepsis group, patients with Gram-negative and Gram-positive infections had similar plasma PCSK9 levels as patients without a detectable pathogen in their blood. In conclusion, the current study suggests PCSK9 as a possible biomarker for COVID-19, but this needs to be validated in larger cohorts.

Association of circulating proprotein convertase subtilisin/kexin type 9 concentration with coagulation abnormalities in patients with primary membranous nephropathy

Objectives The aims of the study were to explore the potential associations between plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) and coagulation indexes in patients with primary membranous nephropathy (PMN). Methods A total of 87 patients diagnosed with PMN were enrolled in our study. 30 healthy participants were recruited to match PMN participants. Plasma PCSK9 concentrations were tested by enzyme-linked immunosorbent assay (ELISA). Correlations between PCSK9 and coagulation abnormalities in patients with PMN were analyzed using univariate and multiple linear regression analysis. Results Plasma PCSK9 levels in patients with PMN were significantly higher than that in healthy controls [232.0 (143.5, 359.5) ng/mL vs. 166.8 (129.7, 199.7) ng/mL; p = 0.001]. Plasma levels of PCSK9 were positively correlated with factor VIII, factor IX, factor XI, log-transformed tissue factor, protein C and protein S (r = 0.267, p = 0.013; r = 0.496, p < 0.001; r = 0.217, p = 0.045; r = 0.584, p < 0.001; r = 0.372, p = 0.001; r = 0.282, p = 0.011). In multiple linear regression analysis, PCSK9 concentration was independently and positively correlated with factor VIII, factor IX, and tissue factor (β = 0.186, p = 0.047; β = 0.325, p = 0.001; β = 0.531, p < 0.001; respectively). PCSK9 concentration was independently and negatively correlated with PT (β= −0.343, p = 0.011). Conclusion Plasma PCSK9 levels had good positive correlations with procoagulant clotting factors and negative correlations with PT in PMN, which might provide novel information with regard to PCSK9 and hypercoagulability in PMN.

PCSK9 Levels Are Increased in Type 2 Diabetes Mellitus with, and without Statin Therapy in Thai Subjects

Background: Plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) levels were found associated with not only lipid profiles, but also glucose homeostasis. Nevertheless, the relationship between PCSK9 levels, and diabetes was inconsistent in various studies. Objective: To investigate the plasma PCSK9 levels among normoglycemia, pre-diabetes, and T2DM patients with, and without statin therapy in Thais. Materials and Methods: Five hundred fifty-three subjects including 213 normoglycemia, 176 pre-diabetes, 46 T2DM without statin therapy, 40 T2DM with simvastatin therapy at 20 mg/day, and 78 T2DM with simvastatin therapy at 40 mg/day were recruited. Anthropometric data, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), fasting blood sugar (FBS), and PCSK9 levels were measured. Results: PCSK9 levels were significantly higher in T2DM without statin therapy compared with normoglycemic subjects. In addition, T2DM with simvastatin therapy (40 mg/day) had significantly higher PCSK9 levels than T2DM without statin therapy, and T2DM with simvastatin therapy (20 mg/day). Serum PCSK9 levels were positively correlated with several metabolic parameters including age, body mass index (BMI), systolic blood pressure (SBP), TC, TG, and FBS (p&lt;0.05) in the present study subjects. Conclusion: PCSK9 levels were modulated by glycemic status, and statin therapy in Thai subjects. Elevation of plasma PCSK9 levels in T2DM with, and without statin therapy may increase the risk for dyslipidemia, and cardiovascular disease among T2DM patients. Keywords: PCSK9, Pre-diabetes, T2DM, FBS, Statin

Effect of empagliflozin on plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) in patients with type 2 diabetes

AimCardiovascular benefits of sodium-glucose cotrasporter-2 (SGLT2) inhibitors occur despite a modest increase in low-density lipoprotein cholesterol (LDL-c). We tested whether the effects of chronic SGLT2 inhibition on lipid profile composition are mediated by elevation in plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) levels inhibiting LDL clearance. Methods78 patients with type 2 diabetes (T2D) received empagliflozin 25 mg/d in an open-label design. At enrollment and after 4-week therapy, fasting blood samples were collected for the measurement of plasma PCSK9, glucose, total and fractional cholesterol, and triglycerides. ResultsPlasma PCSK9 was not significantly affected by empagliflozin (−10.7 [−24.1, 2.7] ng/mL). The treatment induced a mild increase in high-density lipoprotein cholesterol (+1.7 [0.5, 3.0] mg/dL), without significant LDL-c alterations (+1.0 [−4.1, 6.0] mg/dl). Changes in LDL-c were associated with changes in fasting glucose levels (β = 0.320, p = 0.017), but not with plasma PCSK9 (β = 0.010, p = 0.800), after adjustment for age, sex, baseline LDL-c, and body weight change. ConclusionIn patients with T2D, chronic SGLT2 inhibition with empagliflozin has no potentially harmful effects on circulating PCSK9 levels. This finding does not support a pathogenetic role of plasma PCSK9 in the mild plasma lipid alterations observed during SGLT2i treatment.

Hepatic Sensing Loop Regulates PCSK9 Secretion in Response to Inhibitory Antibodies

BackgroundMonoclonal antibodies against proprotein convertase subtilisin/kexin type 9 (PCSK9i) lower LDL-C by up to 60% and increase plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) levels by 10-fold. ObjectivesThe authors studied the reasons behind the robust increase in plasma PCSK9 levels by testing the hypothesis that mechanisms beyond clearance via the low-density lipoprotein receptor (LDLR) contribute to the regulation of cholesterol homeostasis. MethodsIn clinical cohorts, animal models, and cell-based studies, we measured kinetic changes in PCSK9 production and clearance in response to PCSK9i. ResultsIn a patient cohort receiving PCSK9i therapy, plasma PCSK9 levels rose 11-fold during the first 3 months and then plateaued for 15 months. In a cohort of healthy volunteers, a single injection of PCSK9i increased plasma PCSK9 levels within 12 hours; the rise continued for 9 days until it plateaued at 10-fold above baseline. We recapitulated the rapid rise in PCSK9 levels in a mouse model, but only in the presence of LDLR. In vivo turnover and in vitro pulse-chase studies identified 2 mechanisms contributing to the rapid increase in plasma PCSK9 levels in response to PCSK9i: 1) the expected delayed clearance of the antibody-bound PCSK9; and 2) the unexpected post-translational increase in PCSK9 secretion. ConclusionsPCSK9 re-entry to the liver via LDLR triggers a sensing loop regulating PCSK9 secretion. PCSK9i therapy enhances the secretion of PCSK9, an effect that contributes to the increased plasma PCSK9 levels in treated subjects.

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

BackgroundWhether plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) levels is a predictor for cardiovascular outcomes has currently been controversial. No data is currently available regarding the relation of PCSK9 to cardiovascular metabolic markers (CVMMs) and major adverse cardiovascular events (MACEs) in stable coronary artery disease (CAD) patients with diabetes or without diabetes.MethodsA total 1225 untreated patients with stable CAD were consecutively enrolled and their baseline plasma PCSK9 levels were determined by ELISA. Patients were divided into high and low PCSK9 groups according to PCSK9 median. All patients followed up for the occurrence of MACEs and received standard therapy after admission. The associations of PCSK9 with CVMMs and MACEs were evaluated.ResultsPCSK9 levels were positively correlated with multiple CVMMs including total cholesterol, low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol and hemoglobin A1c at baseline (all p < 0.05). During a median follow-up of 3.3 years, 103 (8.4%) events occurred. PCSK9 levels were higher in patients with events compared to those without (p < 0.05). The Kaplan–Meier analysis displayed that patients in high PCSK9 group had lower event-free survival than that in low group (p < 0.05). Multivariable Cox regression analysis revealed that PCSK9 levels were independently associated with MACEs in diabetic patients (adjusted hazard ratio [HR]: 1.361, 95% confidence interval [CI]: 1.037–1.785, p < 0.05). When added the combination of PCSK9 levels and diabetic status to stratifying factors, patients in high PCSK9 group appeared to have extremely high risk of subsequent MACEs with diabetes (adjusted HR: 5.233, 95% CI: 2.546–10.757, p < 0.01).ConclusionsThe present study firstly showed that elevated PCSK9 levels were related to multiple CVMMs and MACEs in stable CAD with diabetes, suggesting that plasma PCSK9 measurement could help to identify diabetic patients with CAD at higher cardiovascular risk. More studies may be needed to confirm our findings.

Does 24-h Activity Cycle Influence Plasma PCSK9 Concentration? A Systematic Review and Meta-Analysis.

Higher plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) concentration has been associated with a higher risk of atherosclerotic cardiovascular disease (ASCVD). Animal and human studies have examined the relationship between 24-h activity cycles (24-HAC) and PCSK9, but conflicting results exist. Therefore, this review aimed to examine the relationship between 24-HAC and plasma PCSK9 concentration in animals and humans.Three databases (PubMed, CINAHL, and Web of Science) were searched for eligible articles. Descriptive data were summarized using network meta-analysis. The effect size was estimated using pairwise meta-analysis. The interventions designed to increase moderate to vigorous physical activities (MVPA) did not significantly change plasma PCSK9 concentration (Hedges' g = 0.137; p = 0.337). However, the effect was influenced by statin therapy and intervention delivery mode. Specifically, physical activity interventions in conjunction with statin therapy significantly increased plasma PCSK9 concentration (Hedges' g = 0.275; p = 0.007). Supervised exercise training significantly increased plasma PCSK9 concentration (Hedges' g = 0.630; p = 0.001), but physical activity counseling did not (p = 0.845). The effects of MVPA on plasma PCSK9 may be moderated by statin therapy, intervention delivery mode, or other potential unknown mechanistic factors. Thus, caution should be taken when using plasma PCSK9 as an outcome indicator for physical activity interventions aimed at decreasing the risk of ASCVD. Graphical abstract.

PCSK9 and atherosclerosis burden in the coronary arteries of patients undergoing coronary angiography

AimsTo investigate the association between plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) concentrations, current acute coronary syndrome (ACS), coronary artery disease (CAD) presence, severity and extension and the burden of coronary calcifications in patients with suspected CAD. Methods and resultsOne hundred and one patients, with or without current ACS, were recruited for this cross-sectional study. CAD presence was defined based on either the presence or absence of at least one significant (≥50%) CAD lesion (SCAD). CAD severity was classified according to the absence of coronary lesions, the presence of non-significant (<50%) CAD (MCAD) or SCAD in at least one major coronary artery. Patients with one, two or three significantly diseased major coronary arteries were defined as 1-SCAD, 2-SCAD and 3-SCAD, respectively. The cumulative length of SCAD lesions and the amount of calcifications in coronary arteries were estimated. Plasma PCSK9 concentrations were higher in patients with SCAD as compared to those without (p = .012). A significant increase in plasma PCSK9 concentrations was observed with greater CAD severity (p = .042). Higher plasma PCSK9 concentrations were found in 3-SCAD patients as compared to either 2-SCAD or 1-SCAD (p < .001). PCSK9 increased with the cumulative length of SCAD lesions and the burden of calcifications (p < .05 for both comparisons). Multivariable adjustment abolished the association between PCSK9 and either CAD presence or severity, but not the association between PCSK9 and the number of significantly diseased vessels, SCAD lesion length and the burden of coronary calcifications. ACS was associated with a borderline significant increase of plasma PCSK9 concentrations among patients not taking statins (p = .05). ConclusionCirculating PCSK9 concentrations discriminate patients with greater coronary atherosclerotic lesion extension and calcification, and are increased in patients with current ACS.

Plasma PCSK9 correlates with apoB-48-containing triglyceride-rich lipoprotein production in men with insulin resistance

Intestinal triglyceride (TG)-rich lipoproteins (TRLs) are important in the pathogenesis of atherosclerosis in insulin resistance (IR). We investigated the association of plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) concentrations with apoB-48-containing TRL metabolism in 148 men displaying various degrees of IR by measuring in vivo kinetics of TRL apoB-48 during a constant-fed state after a primed-constant infusion of L-[5,5,5-D3]leucine. Plasma PCSK9 concentrations positively correlated with TRL apoB-48 pool size (r = 0.31, P = 0.0002) and production rate (r = 0.24, P = 0.008) but not the fractional catabolic rate (r = -0.04, P = 0.6). Backward stepwise multiple linear regression analysis identified PCSK9 concentrations as a positive predictor of TRL apoB-48 production rate (standard β = +0.20, P = 0.007) independent of BMI, age, T2D/metformin use, dietary fat intake during the kinetic study, and fasting concentrations of TGs, insulin, glucose, LDL cholesterol, or C-reactive protein. We also assessed intestinal expression of key genes involved in chylomicron processing from duodenal samples of 71 men. Expression of PCSK9 and HMG-CoAR genes was positively associated (r = 0.43, P = 0.002). These results support PCSK9 association with intestinal secretion and plasma overaccumulation of TRL apoB-48 in men with IR.

Plasma proprotein convertase subtilisin/Kexin type 9 (PCSK9) is associated with Lp(a) in non-CAD type 2 diabetic patients

Type 2 diabetes mellitus (T2DM) is associated with elevated plasma apolipoprotein B, Lp(a), triglycerides and reduced HDL-C. The present study was conducted to investigate whether plasma proprotein convertase subtilisin/kexin type 9 (PCSK9), a regulator of LDL-receptor (LDLr) expression in hepatocytes, was associated with diabetic dyslipidemia. We developed a sandwich ELISA using recombinant human PCSK9 protein and a polyclonal antibody pre-coated onto a microplate specific directed against human PCSK9. We measured circulating PCSK9 concentrations in a cohort of patients with T2DM ( n = 50) compared to an age- and sex-matched control group ( n = 50). Plasma apolipoprotein B, Lp(a) triglycerides, LDL-C, HDL-C and LDL-r were measured in both groups. Plasma PCSK9 levels were significantly elevated in T2DM compared to controls (44.61 ± 14.44 and 33.22 ± 11.79 ng/mL respectively, P < 0.0001). However, LDL-r levels did not differ between the two groups. No significant correlation of PCSK9 with lipid parameters was found. Remarkably PCSK9 was positively correlated with Lp(a) in whole population ( r = +0.254, P < 0.0138) and T2DM group ( r = +0287, P = 0.0474) but not in controls. Lp(a) levels has been proposed as a contributing factor to the accelerated development of macrovascular complications in T2DM and the synergic effect with PCSK9 may explain the enhanced atherogenicity in type 2 diabetic patients.

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.

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.

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.

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.

Association between plasma PCSK9 levels and 10-year progression of carotid atherosclerosis beyond LDL-C: A cohort study

BackgroundTo evaluate the association of plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) levels with the progression of carotid atherosclerosis and identify additional PCSK9-lipoprotein-atherosclerosis pathway beyond low-density lipoprotein cholesterol (LDL-C). MethodsAmong 643 participants (aged from 45 to 74years) free of cardiovascular disease at baseline, carotid ultrasound examinations were performed in 2002 (baseline) and 2012 (follow-up). None of the participants were taking lipid-lowering drugs or had detectable carotid plaques at baseline. Carotid plaque formation and total plaque area (TPA) were used to reflect 10-year progression of atherosclerosis. ResultsBaseline plasma PCSK9 levels have a wide variation, ranged from 64.60–532.20ng/mL (median: 192.57ng/mL). PCSK9 levels were significantly associated with new plaque formation after adjusting for LDL-C levels and other risk factors (relative risk for per quartile increase=1.09, 95% confidence interval: 1.03–1.15). PCSK9 levels were also linearly associated with TPA after multivariate adjustment including LDL-C (P=0.008). Among participants with the lowest or second tertile of LDL-C, PCSK9 quartiles were linearly associated with TPA (P=0.021), but the association lost significance after additional adjustment for very low-density lipoprotein cholesterol (VLDL-C) tertiles (P=0.072). Further stepwise linear regression (entry, 0.05; removal, 0.05) indicated that VLDL-C tertiles could be entered into the model but PCSK9 quartiles could not. ConclusionsPlasma PCSK9 levels are associated with 10-year progression of atherosclerosis. The LDL-independent association of PCSK9 levels may through its ability to regulate VLDL-C levels. Further research is needed to systematically investigate the role of PCSK9 for the pathogenesis of atherosclerosis, beyond LDL-C metabolism.

Marine n-3 polyunsaturated fatty acids lower plasma proprotein convertase subtilisin kexin type 9 levels in pre- and postmenopausal women: A randomised study

ObjectiveTo investigate whether a supplement of 2.2g of marine n-3 polyunsaturated fatty acids (PUFA) influences plasma proprotein convertase subtilisin kexin type 9 (PCSK9) levels in pre- and postmenopausal women. MethodsNinety-two healthy women were randomly assigned to consume 2.2g marine n-3 PUFA or a control oil (thistle oil) daily for 12weeks. Adipose tissue, a long-term marker of dietary intake of seafood was collected at baseline and blood samples were drawn at baseline and after 12 weeks of supplement intake. ResultsPlasma PCSK9 levels were significantly reduced by 11.4% for premenopausal women and 9.8% for postmenopausal women after the supplement of 2.2g of marine n-3 PUFA compared with control oil. The mean change of plasma PCSK9 levels between participants receiving marine n-3 PUFA and control oil was 16.1% for premenopausal women and 13.1% for postmenopausal women. There was, however, no correlation between baseline levels of plasma PCSK9 and the fatty acid content of marine n-3 PUFA in adipose tissue. ConclusionThis study showed that 2.2g marine n-3 PUFA reduce plasma PCSK9 levels in both pre- and postmenopausal women.

Impacts of ezetimibe on PCSK9 in rats: study on the expression in different organs and the potential mechanisms.

BackgroundPrevious studies including our group have indicated the effects of ezetimibe on increased plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) concentration, while the rapid expression in different organs and the potential molecular mechanisms for this impact have not been carefully evaluated.MethodsThirty rats were randomly divided into two groups (n = 15 for each), which were orally administrated with ezetimibe (10 mg/kg/day) or normal saline. Blood samples were obtained at day 3 after orally administration, and the PCSK9 levels were determined by ELISA. We further analyzed the mRNA expression of PCSK9, low-density lipoprotein receptor (LDLR), sterol regulator element-binding protein 2 (SREBP2), and hepatocyte nuclear factor 1 alpha (HNF-1α) by real-time PCR, as well as the protein expression by western blot, in liver, intestine and kidney respectively.ResultsEzetimibe significantly increased plasma PCSK9 levels compared with control group, while there was no significant difference between the two groups with regard to lipid profile at day 3. Moreover, ezetimibe remarkably increased the expression of PCSK9, LDLR, SREBP2 and HNF-1α in liver. Enhanced expression of PCSK9, LDLR and SREBP2 protein were found in intestine and kidney, while no changes in the expression of HNF-1α were observed in intestine and kidney of rats with ezetimibe treatment.ConclusionsThe data demonstrated that ezetimibe increased PCSK9 expression through the SREBP2 and HNF-1α pathways in different organs, subsequently resulting in elevated plasma PCSK9 levels prior to the alterations of lipid profile in rats.

Abstract 131: PCSK9: A Biomarker Associated with the Metabolic Complications of Morbid Obesity

Objectives: Plasma pro-protein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protease that inhibits the activity of the LDL-receptor. Here, we determined the effect of bariatric surgery on plasma PCSK9 levels. Methods: Sixty-five obese patients (BMI : 46.7 ± 6.5 kg/m 2) were prospectively evaluated before and 6 months after bariatric surgery (sleeve-gastrectomy [n=53], Roux-en-Y gastric bypass [n=12], gastric banding [n=1]). Plasma PCSK9 were measured by ELISA and liver mRNA PCSK9 expression by Q-PCR. Results: Before surgery, plasma PCSK9 was positively associated with LDL-C (r=0.59, P&lt;0.0001), plasma triglycerides (TG) (r=0.48, P=0.0006) and fasting plasma glucose (FPG) (r=0.29 ; P=0.036), and negatively with BMI (r =-0.34, P=0.01). Plasma PCSK9 concentrations were increased in obese patients with metabolic syndrome (MetS) compared to those without MetS (295 ± 93 vs 210 ± 58 ng/ml, P&lt;0.0001). Bariatric surgery did not alter plasma PCSK9 concentrations at 6 months. Interestingly, circulating PCSK9 was not longer correlated with LDL-C after bariatric surgery, but remained strongly associated with TG (r=0.50 P=0.0006), FPG (r=0.40 P=0.006) and HOMA-IR (r=0.40 P=0.007). Plasma PCSK9 levels were positively associated with liver steatosis (r=0.26, P=0.05), and were higher in patients with NASH (347 ± 101 vs 228 ± 73 ng/ml, P=0.003). Surprisingly, PCSK9 hepatic mRNA expression did not correlate with plasma PCSK9 concentrations, neither with LDL-C nor TG. Conclusions: Circulating PCSK9 concentrations are associated with the metabolic complications of obesity, including insulin resistance, hyperglycaemia, hypertriglyceridemia and NASH and are not a direct reflect of its hepatic synthesis. ClinicalTrials.gov identifier : NCT00422006